Nihilanthic

I got a 1987 Z28 with T-tops and a little bit of... work done on it for about $300. Has a T-5 and a 3.73 rear end, but I need to find some discs to replace those damn drums!

Anyway, its got a 355 in there, and the guy who had it before me was doing a few things with it. The interior is in bad shape (I'll probably just strip it out anyway, its only a 300 dollar car haha) and I saw Edelbrock's Performer RPM kit. It really caught my eye by being really streetable and still having a big powerband and no real lack of torque in it.

My question is... what would I need to do to give it a 7000 rpm ceiling? I dont plan on going over it, and I dont mind losing a little low end to give it high end (its a manual and I know how to heel toe) and its only a 500 rpm shift. I dont mean like, a redline of 7K, i mean the highest it would ever go is 7K. A "ceiling" so to speak... or does it effectively have one already? The dyno sheet seemed to indicate it would barely stop making power all the way up there.

Also... how much can those damn T-5s take? Would it be worth trying to build it to take the torque of the rpm performer kit (415 foot lbs a the crank) or just go find a T56?

Thanks in advance!

ljnowell

Wow lots of questions here. I guess you could retard the cam, to push the RPM range higher. Not a good idea in my opinion really, especially for a street driven car.

The best thing to do would be to forget about the edelbrock power package altogether. Thier cams suck. I dont mean quality of the part, I mean performance wise. They are lazy and have very poor ramp rates. Look elsewhere for a cam

The T5 can take plenty of power, as long as you dont use slicks and big clutch drops.

Nihilanthic

Well, my current plan is a 7K Ceiling. Not going higher than that. Dont want to have to change out rod bearings, and other **** all the time.

I dont mind losing some low end to get, say, that 3K-7K Rev range I See on some cams. I like shifting on manuals. I learned to drive them on a 1987 Nissan Maxima and a Oldsmobile Achieva, so I can deal with having to shift :P Besides, its a 355 cid V8. How low can the lowend get?

If you have any suggestions, I'm open to them!

I'm on a budget but I'm willing to save up a little to get the right stuff. I got some cast iron LT1 heads from this mechanic for 50 bux(dont ask, but I think he either didnt care about them or just wanted a hit of crack).

Any suggestion on what manifold I should get with that, and what cam? As long as it doesnt feel like someone dropped 4G63 out of an Evo under my hood I'm cool with 'racey' cams.

I got a exhaust system waiting until I can borrow a pickup or van to carry it over, and the Holley 650 CFM is already sitting on top of the engine.

Stekman

Why exactly do you want a 7000 RPM powerband? It's not like you will be making serious power up there with the RPM combo. Does Edel. advertise a 1500-6500 RPM powerband? Yes. Is it a cam that can deliver up there? There's better. For the street, I really doubt you need more than 6500 RPM, 6000 maybe, even with a T5.

My rundown of the combo:

Intake: Great intake for the street.
Heads: Good head, is there better, sure. Is there worse, absolutly. It will suffice.
Cam: Much to be desired here.
Carb: Don't want to start the Edel. vs Holley debate.

I suppose here's my question to you: What are the exhaust plans? FULL exhaust.

Nihilanthic

From what my old man (Stepdad) tells me the guy we got that Z28 from has a full exhaust sytem in his garage but I need a damn truck or something to bring it over. From what I know its a full headers and true dual pipes setup. Not sure of measurements.

As it is right now.... the Z/28 doesnt really have much except headers and that pos y-pipe.

I mean obviously I gotta go to Scott's house to get it but meh.

As far as 7K... it was just a goal more or less. A proof of concept that I could do it on a streetable v8 and just something to tease ricers with who bitch about low revving engines. But, if 6.5 or 6.8 does it, its all good. If it proves to be unfeasable with available camshafts, then so be it. I got the idea when I saw how flat the power curve topped out at 6.5 on that dyno.

I got those cast iron LT1 heads... What can I do with them?

ME Leigh

I'd go with a solid roller cam, something like XR274R or one step larger if your feeling lucky.

The LT1 can be retrofitted to work on a GEN I SBC, do a FWIW i'm retrofitting some AL LT1 heads for my 305.

Full exhaust and headers is gonna be your friend no matter what. It is a necessary upgrade.

Nihilanthic

Its a 1987... What do I have to do to it?

BTW its a 355 not a 305. Bored out 350 :P

Whats the rpm range of the XR274R cam? Who makes it?

What are the characteristics of the LT1 head? what rpm range does it end up falling on its face? What kind of intake manifold should I use? lol.

Again, I got a 5 speed and I grew up on those peaky japanese cars, so I like having high end that pulls all the way to redline.

My Stepdads 1988 IROC-Z (TPI, 4spd auto) is punchy and burnouts like a pro but it just runs out of breath by 5500 rpms.

Nihilanthic

Ok, I'm canning the 7K idea for now. Kind of meaingless and absurd because I'm almost surely going to lose driveability with it. My original reasoning is if some Evo can live 3K-7K all day, why cant I?

"My rundown of the combo:

Intake: Great intake for the street.
Heads: Good head, is there better, sure. Is there worse, absolutly. It will suffice.
Cam: Much to be desired here.
Carb: Don't want to start the Edel. vs Holley debate."

That was Stekman's analysis of the rpm kit from edelbrock.

Ok, so the cam sucks, and you dont wanna get into the oranges vs tangerines debate about carburators.

Well, given that 1.5-6.5K revrange of the rpm kit, and you saying that I could go better with heads and cams... any reccomendations?

I have LT1 heads, cast iron, sitting in the back seat of it right now. Would those suffice? Any cam ideas?

F-BIRD'88

If you really want a 7000rpm rev-er
don't use the performer RPM or a hydraulic cam.

Use a single plane intake like a Vic Jr.

Get a solid ( mechanical) cam with a duration of 244 to 256 at .050"
This cam will require specific hi-perf springs . Look at the Crane cams Saturday night specials. They come as complete kits and work great.
You want to raise the motors compression ratio to 10:1.
get some small chamber heads and port them your self.
L-98 TPI heads 305 tpi heads
305 HO heads ( 416) among others work well for this.
use a 750cfm carb. Doesn't matter which
yes it will have a a rough idle.
and reduced manifold vacuum. The motor will run fine once you've modified the distributor for increased
initial advance. (limit the advance travel) 24 degress initial at idle with 32-36 total at 3000rpm
With a 5 speed you'll want at least 4.10 rear gearing with a motor like this.
Power will be 3500 to 7000rpm.
I built just such and motor using my ported 305 heads, it was an absolute hoot, Would buzz to 7000 rpm ++
Piston to wall clearance and the ring gap needs to be a few thou bigger so don't be shy honing the block.

Nihilanthic

So, you built such a motor yourself? Sweet!

What would this feel like on the street? I know it has a lack of low end - but I have a 5 speed, and all those new turbo AWD cars dont have any low end either :P

What did it feel like when you got on it? I know if the gears are properly spaced you wont fall out of that powerband on upshift, and the lack of turbo lag would make it tear asphalt off the road out of corners!

Would the off-cam gas mileage (Below 3K) be good, or bad?

And, say I wanted to build a copycat of the RPM performer kit (I've had some guys say that certain components could be a lot better than whats included, such as the cam and head) Would you have any suggestions?

420 HP and 'streetable' torque is going to be a monster, period. If I bump it up to the 3K-7K motor later on I'm going to sound like a rolling explosion and see north of 500 hp. I think I should do it in stages so I dont wake up some morning with a demon I cant handle yet.

BTW, I do have cast iron LT1 heads I'm going to adapt to the 355 block sitting in the engine. What flow and rpm range can they handle? I've done searches and all I've seen is they allow you to rev higher and dont have the insane lowend of TPI.

F-BIRD'88

Sounds like you've been getting a lot of conflicting info.
Cannot compare this to a Honda or any other small motored car. If your power to weight ratio is lower ( more power per pound) the car will accelerate faster,
end of story. So if you want to smoke Hondas, calculate the hp/lbs and build your Fbody accordingly.

The Edelbrock RPM package is not to bad. If your build the combination "to spec" it will deliver as advertised.
But it is not a 7000rpm rev-er.

The RPM heads are good and can be improved with porting.
Hydraulic cams tend to have a built in rev limit of about
6200 to 6500 because of lifter pump up. If you really want to buzz it to 7000rpm + use a solid lifter cam.
The motor will make more power overall and rev easily.

It does require periodic valve lash adjustment but not a big deal once you've done it a few times.

The potential of factory LT1 heads is good once you've ported them and increased the valve size. But modifying the water outlets in the deck face is a bit of work.
They can be ported to exceed the power level of even stock edelbrock rpm heads. The rpm characturistics of a LT1 motor is more affected by the factory short runner LT1 intake manifold compared to a long runner TPI intake than the heads.
The LT1 heads are a lot like vortec heads, if you want to go that route, sell off your LT! heads and get vortec heads to start with.

Any motor that makes over 400hp will not be great on gas so be sure of what your really want. If you really want a gas savery commuter you're headed in the wrong direction.

A high reving motor like this requires a rear gear ratio change. Don;t expect this to perform to expectations with stock rear gearing. Also requires a hi flow exhaust system.

Nihilanthic

lol, I know its weight to power, not displacement to power ratio. I also played around with some math one day and it seems you have to rev to about 8500 rpms with any given displacement to move the CFM to get that magic 100 hp/liter number.

So, obviously, you'd have ****ty low end with only one cam profile, so only the VTEC or VTEC-like imports go that high revving NA route on the street. I could just as easily get a blower or turbo and spank them with half the rpms anyway

(part of my goals are to kind of prove some concepts to the ***** boys. Every damned buzzing honda with a fart cannon wants to race me around here.)

I also know I can't get the flexibility and easy to use lowend of the rpm kit if I also want to go up to 7K without falling on my face, but I was wondering how I'd do something like that RPM kit - with the said LT1 heads and better components than the cam included like that one guy said - and get used to that BEFORE I try to go out and that your 7K rpm revving monster.

I was initially gonna do what you did but I havent seen a dyno yet, so I dont know what kind of power/torque it makes between idle to 3K when its "on the cam". Plus, 420ish out of only 6.5K and easier lowend would be better to 'learn' to handle this kind of machine on than just jumping headfirst into basically a race engine.

And um... yeah, I know I'm full of these damn questions - part-throttle wise... would I burn less gas "on cam" or "off cam" at the same rpms.

Like say, basically the same engine, just one has a truck cam and one has that 3K-7K cam. I shift at 3K at most driving in the city. which uses less gas?

F-BIRD'88

"100hp/Liter" Is that what you want?
You won't do that with edelbrock RPM heads, LT-1 heads or any other hed like that. Thats 570HP on a 350CI motor.

You can built a 570hp small block, and drive it on the street, and rev it to 7000rpm, but it will not be good on gas. It will go fast, thats for sure. You will need the best of everyting to build such a motor. And it won't be cheap.

A big block is cheaper and more durable overall when you get to this point.

I don't quite get what your asking about off cam low rpm cruising. Will the car drive ok? yes will it have enough torque? yes. will it need higher rear gearing to work best? yes. Will it be as good on gas as a stock motor? no. will it be terrible? depends on your realistic needs. Will this be a good commuter combination? no.
Will it pass and emissions test? no.

Will it smoke most typical honda's? yes. But a Honda, even a stock Honda will still rev higher.

Don't build it half ***. Some of this and some of that. Oh I'll just substitute this ofr that, I'll change this later etc etc. Check your wallet, decide that your goals really are and your realistic needs are and build it right accordingly.

An Edelbrock Victor JR. Combination will make about 570hp. the basics are a 12.5:1 compression 350ci motor with Edelbrock Vic JR heads, a .600" lift 265duration @.050" roller cam with roller valvetrain , big tube headers, 900cfm holley carb and high octane 110+ racing gas.

Nihilanthic

Naw, this engine is gonna be street driven, and taken to a dragstrip on some weekends. I was just explaining where I got the ideas from. If I wanted streetable 100 hp/liter I'd get a turbo or blower. Its not my goal, sorry I was unclear. And because I can only use one cam at a time in a SBC - I dont plan on spinning up to 8-8.5K and dumping gas into my carburator :P

Half of it was thinking out loud about how to do it. I apologize for rambling so much!

The question was.... driving at city speeds not going above 3K, would I burn more or less gas on a truck cam or a race cam (like your 3K-7K)? Lower vacuum = less air going in, and thus less fuel, right? Or am I wrong? This isnt really gonna be my commuter car, just a question because if you make less power at those rpms on the race cam, I figured it might use less fuel.

Im trying to emulate the RPM kit with what I have and replacing parts I've been told arent so great (like the cam) with something else to build it up myself. I didnt mean "building it half assed", I meant I was told the cam with the kit isnt that great, so what would be a BETTER choice, than that cam.

LATER ON, I might want to get a new intake manifold and cam, and any sort of valvetrain necessary, to pump it up to that 7000 rpm revving demon you built. But for now, I'm having second thoughts. I might not be able to handle it yet!

After thinking about it something like that rpm kit would be easier to live with and get used to before I jump into something as racy as my 7K revving idea. Also, by then I'd want to get a little commuter car to use so I wont burn all my gas away on that engine with high *** gears. Right now my car has a 3.73 rear - would that "RPM" kit work good with that ratio?

Again, sorry I'm saying so much in one post!

F-BIRD'88

You will get less gas mileage with the race cam regardles of how you drive it.

If you build the short block to spec, the Performer RPM package will deliver as advertised. If you build something else, expect a different result. A better, but still simular cam like a Comp cams extreme energy cam will make a bit more power, but not a lot more. maybe 10-15 hp more at best. A comp Xe274 or comp Xe284 would be such a cam. The edelbrock cam is a good cam (for this combo), the Comp extreme is a little better. The comp cam needs a little better valve spring. it lifts the valve a little faster.
The final rpm limit is about the same, just makes a bit more power.

either way you'll want some performance gears. What rear gearing do you have now?

Nihilanthic

So... the milder the cam the less gas period? I see.

Um, its 3.73 right now. That rear end also has drums on it (I'll see to fixing that ASAP ) would those be short enough?

BTW, thanks for answering my cam question. Now... would the LT1 heads be sufficient if I retrofit them and port them properly? The ones I got already have bigger valves in it, just need to be cleaned up a little.

I also basically have free flowing exhasut for free, but I gotta wait until I have a way to GET it over here. I need to borrow a van or truck.

F-BIRD'88

3.73's are ok.

Stock Lt-1 heads flow about 200cfm@28" on the intake side. They have a pretty good exhaust port about 150cfm. out of the box Edelbrock heads flow about 232cfm and 170 on the exhaust side. if you want the LT1 heads to perform like and make the same power as the RPM heads you will have to fully port both the intake and exhaust ports.
Use 2.02 x 1.60 valves. I believe 1.94 x 1.50 is the stock valve size. Minor chamber deshrouding will improve flow with the large valves too.

can be done but you'll have to put the work into it.
Do not pay someone to port your stock heads. Do it your self. its not real hard to do, just time consuming.
Other wise just buy a hi flow head like Edlebrock heads or what ever.
Spend $10 on a good head porting book like the ones by David Vizard. All the basic info is relevent to porting LT1 heads. there is no reason why you shouldn;t be able to achieve 230-240cfm after fully porting these heads yourself useing the info from these books.

Here is an online article on porting vortec heads. the job is the same for your LT1 heads.

Nihilanthic

Lol, the ones I got have those valves already. I just gotta port it out. Apparently its also had the coolant passages set up right, but all I need to do is seal off one of them. A gasket should be able to take care of that just fine.

Now, sorry again but I got another question:

420 hp is less than 650 cfm, right? (givem 150 cfm per 100 hp)

Well, um... 650/8 = 81.25... 200 cfm is nearly a third of the total airflow moving at once.

How much flow at the intake port do you need as a fraction of the total CFM you're moving, anyway? Is there an equation?

F-BIRD'88

You're going to get yourself very confused. Don't equate head flow figures @28" pressure drop with carb flow @1.5".
If you want a ball park head flow requirement to get X amount of Horsepower from an engine there is a basic formula.
This formula is based on an optimum tuned motor under optimum conditions. This is gross flywheel hp on a dyno You can realisticly expect 90% of the calculated result on a decent street Small block chev motor ( again gross flywheel HP on a dyno). multiply the intake ports best flow figure at 28" by .2575 and then by 8 ( for a V8) so 230cfm X .2575 X8 equals 473.8 hp 90% of which is 426hp. for typical *realistic* rear wheel hp in your car multiply this result by .8 or 340hp.

The 340hp is the number you use in any power/weight speed "dream wheel" calculators.
In a typical 3550lbs fbody that works out to be about 107mph in the quarter mile. Good enough for mid 12's with traction.
A 750 to 800cfm 4barrel carb will work best.
So, How fast are the pesky Honda's?

For top speed, your 3.73's combined with a 26" tall rear tire will be just about right ( top of 5th gear) about 150-155MPH {6200-6300 rpm}
For best quarter mile acceleration a 4.56:1 rear gear would be optimum with a 26" tall tire (allows this motor to peak out and apply all the power at the top of 4th gear) with such a motor ( assuming good traction)

Your 3.73's will be ok.
A stock motor idles about 600rpm and peaks out about 4500rpm. Your accessory pulleys are optimized to make the accessories (alternator/ waterpump/fan/ power steering work best within this engine speed range.
a modded engine like this will idle higher (about 750/800rpm and peak out higher 6000-6500rpm.
Your accessories will suck a huge amount of power if they are overspeeded. You'd want to reduce the pulley drive speed ratio by about 25-30% (smaller crank pulley/larger accessory pulley) because the optimum accessory speed does not change.

Nihilanthic

Ok... so cfm x .2575 x # of cylinders = horsepower I can realistically expect those heads to support. HP x 1.5 = how much cfm the carb would need? Thanks for what you gave but I'm trying to figure out the carb cfm/head intake cfm ratio.

Why do you think I'd need a 750? 355 ci @ 6500 rpms is about 667 cfm. At 100% VE. wouldn't a 650 or 700 be sufficient? or is it better to err on the large side? I'm not questioning you, just wondering how you got that #. I'm still new to this.

The hondas? Not fast at all, probably just an exhaust job. I just dont feel like racing on slicked rear tires in the rain in CARY NC. Their cops are everywhere. Almost EVERY friend I have has been pulled by them. One... becuase he had too much chocolate in his blazer. (he worked for eckerds... and this bunch of chocolate expired, so they let him take it home but the stupid cop called a drug sniffing dog.)

I *HAVE* seen one honda short shirting and popping his BOV at my college, but I doubt I'm gonna have to worry about that kind of ***** much. Besides, when I'm done with all of this 350 whp is plenty -and I still have a long way to go with turbos, blowers, etc.

I'm also going to strip it out for weight saving anyway. Interior is shot. What do I care? lol, I got it for 300.

F-BIRD'88

You have to qualify a carbs cfm rating to the pressure drop. A 4bbl is rated @1.5" of vacuum.

A 355ci motor at 6500rpm will consume 667 cfm assuming 100% volumetric efficientcy.....BUT the manifold vaccuum will not be 1.5" It will likely be .5" to .75" worst
case 1" vaccuum. (@maximum output) Now to find the right carb you have to convert the cfm rating@1.5 to a cfm @ 1" so it needs a 707cfm carb or a 943cfm carb if the manifold vacuum is .75" @ max output.
A dual plane manifold like a performer rpm likes a little more cfm that theory perdicts because each cylinder only sees half the carb. about 20-30% more cfm.

Even thou the motor will not be 100% efficient, a 750 is not too big.

A 750cfm carb has been found to provide about the best
*compromise* between idle, torque, throttle response and top end horsepower on a typical 350 based performance motor. It only compromises the top end a little from optimum. A 667cfm@1.5" carb on this motor will work well, but will compromise top end power output especialy on a dual plane intake.
probabily a 10hp difference.
Surely they have dragstrips in N.C. Thats the place to do you Honda smoken'

Nihilanthic

Interesting...

What are the forumulas for this?

P.S. - yes, we do. It IS NC. And if it wasnt raining or I had decent tires I'd gladly have blown him away

F-BIRD'88

If ya want to go fast, ya gots to know the math.

To find the cfm of a carb rated at 1.5" vacuum at a lower vacuum point like 1" or .5" vacuum you multiply the change in vacuum by .707 (inverse of root mean square)
{root mean square is 1.414}

eg: a 750cfm carb flows 707cfm @1" vaccuum drop.

1" x 1.5 equal 1.5" (pressure drop change)
1.5x.707 = 1.0605 Factor

750 / 1.0605 = 707.

carbs are rated @1.5" vacuum.
it has been shown throu dyno tsting that a engine will perform best and reach its maximum output when the carb is sized to achieve a manifold vacuum reading of .5 to 1" at max output not 1.5" when the carb is sized to achieve a manifold vacuum of 1.5" at max output, the power is a little less, but the throttle response is a little better.

Hook up a manifold vacuum guage in your car and go for a ride.
have a friend watch the guage while you floor it and see what it reads at maximum engine speed at WOT.
If it reads much more than 1.5" your carb is too small or the air cleaner is restrictive. If the guage reads much less than .75" to 1" at WOT max rpm, the carb is probabily too big for your motor.

Red Devil

FWIW as a side note, I have seen a few cars improve at the track with just a switch from an RPM and RPM airgap to the vic jr. Personally my favorite wet flow manifold for the street. It also seems to work surprisingly well with a wide variety of cam profiles. A bit unconventional? Yes.

Nihilanthic

Perhaps so, but I'd kill my low end on the street.

It might be a good bolton if it would make appreciable torque gains in midrange and high end for a track or dragstrip but wouldnt it... SUCK for street driving?

Red Devil

You may be surprised. I sure was a few times before I got it. :shrug: I've only seen 3 or 4 swaps from dual planes for actual comparisons, but I have put them in a few other cars with decent results. Hell, I had a second gen running one with a performer cam for a week before the new cam came in and it wasn't too shabby at that.
You should hop into the carb forum and see if anyone else has had similar experiences. The Vic Jr. is one of the many things I don't quite get.

Nihilanthic

If I could have anything I wanted, then I'd see a dyno of a setup with the RPM manifold and then with the vic jr bolted on!

But I guess I wont. I guess it might not be in the rpm range and flow range it was really intended for, but if its the right cam on the wrong intake it wont be terrible will it? lol.

blacksheep-1

I'm working through this myself, as I'm currently building a 350 for my 83/T5/3.73 car.
Here's some (reasonably well documented) engine combinations.
hope it helps.
http://www.ryanscarpage.50megs.com/combos1.html

F-BIRD'88

"If I could have anything I wanted, then I'd see a dyno of a setup with the RPM manifold and then with the vic jr bolted on!"


Here is a dyno comparision between a RPM intake and a Super vic manifold on a simular engine You can expect the same trend on your engine.

Basicly the vic JR just starts to make a little more power above 5000rpm
If the car is geared to peak out in the quarter then you'd probabily see a gain, especially if the cars has a traction problem. But if the car is under geared the engine will spend more time at the lower end of the power band and a Dual plane will work best.
This engine is right about at the cross over point. A milder engine will definatly like the dual plane better , a more radical hi rpm motor will make better use of a hi rpm single plane.
Both these maniflold are very flexable.
If a modded 750 was used on the Dual plane ( 820cfm) the power difference would surely be made up for at the top end between the two manifolds.
A dual plane with a split plenum can easily tolerate a larger flowing carb then theory would indicate because the metering signal is much stronger and each cylinder see's only one side of the intake plenum. the dual plane cruises much nicer at part throttle also.

Nihilanthic

Interesting... vortecs are like LT1 heads, right?

So, I just get a good manifold and cam and if I adapt my LT1 heads I could see the high 300s to 400 if I go get that exhaust... though right now I'm unsure of the compression

I only got the damn thing for $300, though, and those heads were for $50... so I cant complain too much

F-BIRD'88

Vortecs are more like the LT-4 heads
( raised intake port, improved flow)

The factory Lt-1 head will need porting to equal the flow of a vortec head

If you're looking for vortec head performacne I'd carefully look at the total cost of getting you Lt1 heads upgraded/ refurbished and retrofitted.

May be cheaper overall to just get some vortec heads to start with.

Nihilanthic

I already HAVE the LT1 heads for basically free (50 bucks) and I can port them myself. I just need to get them hot-tanked to clean them up real good.

Would just getting a gasket that can plug up that one coolant passage work, or would I really need to fill it in? BTW, theyre cast iron LT1 heads.

F-BIRD'88

No the head's deck water passages need to be welded closed. And remachined. It's possible to do this but quite involved. There is no gasket to adapt a gen II (LT-1} motor's cylinder head to a GEN I (55-89) block.
The water passages are all different. Unless your a machinist you should carefully calculate the cost of these mods. Even thou You're getting the bare heads cheap, you'll have more in them when you're done then just starting with a Gen I head and work form there.

A 305 TPI #081 or L-98 350 TPI head #083, in modified and ported form with larger valves has tons of power potential.

trade your LT1 heads off on a pair of these common heads and port them. Easy 425 hp with the right combination.

vejatabul

my vortec headed motor had only a set of manley ss valves(stock size) with a 30 degree backcut. it had the factory pressed in studs with a comp 284xe(.507/.510 240/246 on 110) and had the valve guides cut down .100. it had a gm intake w/ holley 650 dp. the heads sat on a factory 1988 chevy truck 350 short block that had never been apart.i had a msd 6al box and the timing locked out at 32 degrees. it had a set of flowtech shorties with 1 1/2 primarys and a 4 in mufflex. it had a th 350 that was stock from a junk yard, out of a 1978 chevy van, i didnt even change the fluid. it had a cheap 3200rpm stall(the major downfall). i had 3.27 gears in a 9 bolt and lakewood lca's,and panhard, and relocation brackets from bmr and no sfc's. the shocks and struts were kyb gr2-s and it had eibach sportline springs. it had 16x8 gta wheels and bfg 255/50/16 drag radials. it was in my 1988 camaro sport coupe. it weighed 3180 with out me. it ran a 7.99 @ 85.2 with a 1.69 60" at denton(1/8 mile) the only time i took it to the track. thats roughly a 12.45 1/4 mile. i ran this on 87 octane gas, which i always ran.
i built the entire motor for $2299.
$100- short block with 20,000 miles
$500- vortec heads complete w/ lt4 valvesprings and titanium retainers
$100- gm vortec intake w/ bolts
$90- comp 284xe cam
$56- comp lifters
$7- moroso chomoly oil pumpshaft and oil pump stud
$12- melling standard volume oil pump
$50- one piece rear seal oil pan
$50- arp head bolts
$45- aluminum water pump
$224- holley remanufactered 650 dp
$107- cvr starter
$40- flexplate
$80- dui hei distributer
$5- msd 6al box(bought box and a coil for $40 and sold the coil for $35)
$12- fel pro intake gaskets
$28- comp true double roller timing set
$24- comp cush rods
$60- aluminum valve covers
$11- fel pro one piece oil pan gasket
$10- alt brackets
$62- 100amp alternator
$159- howe aluminum radiator
$100- flowtech headers
$85- flowtech y pipe
$250- mufflex 4 inch exhaust

the trans was a budget affair also.....
$75- th 350 transmission
$174- boss hogg converter, 2800rpm to 3200 rpm
$107- driveshaft( for the shorter th350)
$85- b@m conversion kit for the th350

the motor ran its best time launching at 2600rpm then shifting at 6800rpm into second gear and into third gear at 6500rpm. many times i took it to 7000rpm. i once even took it to 7500rpm(on accident) under wide open throttle in third gear....and remember this was a stock 2 bolt main short block. and do you know which part failed first?
it was the cheap torque converter. it ballooned and took out the motor and trans, but i still managed to drive it 60 miles home. if you do the math for my relativly light wieght(3250lbs with me in it) camaro, i was making about 320rwhp. now i never made that much on the dyno, i never made more than 245hp! i post all this info just to give you an account of what could be done with not a whole lot of money, but can give you alot of pleasure for only the cost of 18mpg on the freeway! yes, i got 18 mpg with the timing locked at 32 degrees, a double pumper , a 240/246 degree at .050 cam and a 3200rpm stall on 87 octane. i say good luck and do alot of research to build a combination of parts that will give you the results your looking for.