palric

iTrader: (1)

Ok, your first question is why would you bother trying to make 400hp out of a 305 ? Well I probably wouldn't, I just found the article interesting. I got it from someplace off the web...


Begin
********************************************
400 HORSEPOWER 305

This is a summary of a 400 HP buildup of the good old L69 9.5:1 V-8. First, the goodies:

L69 9.5:1 short block w/ 350 rods
Comp Cam 224 deg.@.050", .501" net lift, 110 deg. lobe separation.
RHS 041 heads, 59.0 cc, 1.94/1.50, mild porting, polished chambers and exhaust ports,
Manley Pro Flo valves, Crane roller rockers
Edelbrock Victor Jr. intake, minor-work in plenum area, port matched
650-cfm Holley double-pumper
Hooker 1 3/4" primary tube headers
MSD Extra Duty distributor, Blaster 2 coil
Hamburger windage tray and scraper inside stock oil pan

Engine Dyno numbers:

RPM Horsepower Torque
3500 210 314
4000 243 319
5000 270 320
5500 316 331
6000 361 344
6500 378 305
6850 386 296
7250 402 287

Chassis Dyno numbers:

RPM Horsepower
7000 300

The article claims a true 10.6:1 compression ratio. When block work was done to bore and hone everything,
the deck surfaces were not parallel and the cylinder bores were out of square. The authors felt that the
late-model blocks seem to be made of inferior material that is dimensionally unstable during hard usage.
Pushrods some .100" shorter were used to correct a slight rocker arm geometry problem.

The authors were "genuinely" surprised at the amount of power and the degree of driveability the package
displayed. In early testing, the Z28 ran 106 mph in the 13-second bracket.

***********************************************
End

Interesting eh ? It seems the issue is building the 305 to handle very high (for a 305) rpms which to my mind makes the cost prohibitive. Might as well build a 350 for less hp and more torque ?

I have been reading articles on hi revving SBCs for sometime now. This because I have been considering selling my Formula and buying a low mileage '85 IROC (which was what I was originally looking for when I stumbled upon the Formula last year). I had originally planned on doing an engine and drivetrain buildup to an '85 hardtop IROC. Specifically, a building carb'd 302ci with 6-speed conversion and 4.11 9 inch r/e.

The 302 I have been building on paper makes minumum 375hp and 350lbs torque and revs to 7800rpm. Pretty crazy eh ? The motor will cost over $6k CDN to build and that does not include induction. Ouch $$$.

Waddya all think ?
RP.

johnyIROC

Yeah.... 305's are great! I have a pile of LG4 on my garage floor if anyone wants it....

nblanchard

Hey palric... why is the 302 so expensive to build? It should be just as expensive as any other small block chev. The only expensive part I would see is the crank shaft.

palric

iTrader: (1)

Hey Nathan, yes the crank would be a big dollar item. But so would the rods and pistons. Have to buy high end stuff to make the power (which in this case means handling the rpms).

Worse, the heads are about $2500 CDN (AFRs) and that does not include porting, etc. The block would need to be aligned, honed, squared, magnafluxed or sonic tested for micro cracks. Cam, roller rockers, it all adds up really quickly. A decent crate motor costs $10k CDN nowadays.

It is easy to make power to 5500rpm in an SBC. To make that extra 2000rpm is where it gets REALLY expensive. For what it is worth it would cost you similar to build a 350 to run at 7500rpm (and last for than 10 minutes). Building an engine to survive at high rpms always means much $$$. I have been checking into the 302 because it is uncommon and I want to do something unique.

Hey -- the snow is sticking. What happened to spring ?!?!?

RP.

johnyIROC

Why the short stroke/High RPMs? Are you planning on doing alot of circle track racing? I think it's a cool combo.... my dream engine project is a TT Aluminum 400.

nblanchard

palric.... why are the heads more expensive? When I build my 302, either for the GTA or my buddy and I's future project car, I will be using a 350block and a custom crank. The original 302 used a 327 block and a 283 crank.... the 327 block has the same bore as a 350, if I'm not mistaken. So anything that fits a 350 can be used. Yes yoou need forged everything on the bottom end.. but thats the same for any reliable engine

palric

iTrader: (1)

A twin-turbo aluminum 400 ? That would be OUTRAGEOUS. A 400 sbc is another of my favourite ideas -- an easy 300hp and 375lbs torque with very little cam and head work. Very streetable. Thing is I have not been convinced that it would cool properly and also have not heard good news about hooking up a T-5 or T5-6 to one ?

The 302 is just 'because'. I suppose when I was a 10 years old the DZ302 Z28 was the KILLER app and I always wanted to build one. I've done the 305-350 conversion already which was cool. Got more coin now, older -- guess I am tired of running out of rpms and having to shift so much ?

RP.

palric

iTrader: (1)

Well the heads I am after are AFRs and they are unfortunately very expensive. I think about $2500 CDN but have heard as much as $3000 CDN ? As I said the block work will be expensive (only had rough quotes on this) and the rotating assembly as much as $1500 CDN ? Need new roller cam, roller lifters, and roller rockers for another $1k. Assembly and prep and about $6k in all last I tallied it up. Kinda depressing eh ?

Oh yeah don't forget tax ! $15 tax for every $100.

RP.

nblanchard

Yeah.. building any good engine is expensive. The point I am trying to make is, that the 302 shouldn't be too much more than a comparable 350, since it uses the same block. If I wer to build an engine, i wouldn't waste my time and money on an inferior crank and rods, even if it was just rebuilding the stock 350 in the car now. If you ask me.. $6000 for a 302cid is pretty damn cheap in my books. heck I just priced a lightweight 302 bottom end kit (crank, bearings, billet rods, pins, pistons, rings, etc etc.), and it was 4300bux USD with balancing. Tack on about $2000 USD for the Trickflow Twisted Wedge heads I want.. and thats $6300 USD.. then the cam.. etc etc.. I'd say about $15,000 CDN for the engine I will be building. Yeah, expensive... but I don't plan on ever tearing that beast down again, cause everything should take the power output.

Won't be starting the project anytime soon... but I will build it froma 4bolt main 350 block, then throw a decent TPI system on it. I think they can breathe high RPM... Ford's 5.0L EFI system has just as long intake length.. and it revs. I will have an engine on paper soon.. I will share it with ya if you want. I just have to take a day and work on it. There's so much out there, picking the right combo is such a job and a half

IROCKER

I think you should sell me your Formula!

palric

iTrader: (1)

No, sorry it isn't for sale anytime soon. It is just too nice a vehicle to let go of. I get a kick outta people who see it for the first time cannot believe the showroom condition on a 12 year old car.

RP.

nblanchard

You gotta see BILLZ88350's Formula... want to see showroom... its nuts... it makes me look at my car in disgust. I wish I could've owned my GTA from new, cause then It would be in mint shape... but nope... I was only 11 years old in 1988... LOL

palric

iTrader: (1)

Hmmm... I would like to resolve my need-for-horsepower and stay with the TPI car. Do you know of anyone on the board who has achieved 1 hp per cube NA from a TPI 305 or 350 ? I bounce back and forth between doing a TPI buildup (seems to be alot of dead ends for power there) or buying a carb'd 3rd gen and building power the old fashioned way ?!?!?!

I respect the Ford EFI 5.0 for it's power but thats about it -- I have nothing polite to say about Ford otherwise.

Nathan I would be VERY interested to see your solution if it is TPI based. The last TPI car I drove that made serious power was a 92 Z28 (orange stripes -- does that make it a '91 ?) back in 1993. It had a 305 with the complete SLP treatment (TPI, heads, cam) and was about the fastest 3rd gen I have ever driven. I wish I knew what internals were used -- if I did I would copy it on my Formula.

thx,
RP.

nblanchard

I do not see why TPI can not make the same or more power than a Ford 5.0L HO EFI system. The only solution I can see is a better flowing intake base and large tube runners (or even siamesed). I think the TPI's hugest restriction is the heads, its like drinking beer through a 2mm straw, its just doesn't satisfy. This is theory.. but I can gurantee a huge HP increase with a heads and cam swap, including the intake base. HP = Engine Flow Characteristics. It is harder to get more HP from a 305 because GM is dumb.. LOL.. a small bore and a large stroke, stupid if you ask me. I've always looked at it like this... Bore=Horsepower, and Stroke=Torque. Make your formula a TRUE 5.0L Chevy I don't know why GM didn't make the 302 after 1969 ( I think that was the last year). Would have been nice to have a stock 302TPI chev.

I plugged in a 302 setup with Wedge fully ported (2.02" Intake, 1.6" Exhaust) heads, crower cam, 700cfm TPI, large tube headers w/mufflers, and I got 380 horse and 380ft/lbs... I like that, because the hp and torque is matched...

palric

iTrader: (1)

About the Chev 302 -- I couldn't agree with you more. I actually started a thread on the large board (3rd gen) sometime ago, about builidng a 302ci for the TPI and got trashed for the notion ! I think their point was TPI's won't rev with the 302 configuration, it will get awful gas mileage, there would be no bottom end torque, the engine would fall off just as it was reaching HP peak, etc. My 302 idea had no support so I just let it go.

But CFM is CFM right ? I figure that if you build a system to flow 750 CFM what difference does it make if it is EFI'd or carb'd as long as the fuel is delivered on time ? I have been wanting to build a 302 to match the 5.0 decal on my hood. It would be a very interesting challenge to work out a config that kept the TPI at the same time.

RP.

nblanchard

Well palric.... Challenge them next time you post it... no body ever gives you a solid reason why TPI engines can not rev. The only reason th at seemed believable was the fact it had long tube intake runners, which means more torque... but the EFI 5.0L Ford has just as long intake runners, if you look at it, it makes a loop kinda. I thought it cam in the TB and straight in, but one of my Ford friends (i have very few of these ) said that it comes in, turns underneath, then enters the base. So Fords runners are just as long, if not longer than ours. My buddy has a article where someone used TPI and is pushing over 400 horse easy. It people like tham on th eboard, that make me want to build this engine anyway, just to prove them wrong!!

And the no torque thing.. this is true, you lose torque, which is a given because its a shorter stroke (Force x Distance = Torque, shorter stroke = shorter distance = less torque) I am sure you knew that. But you gain horsepower, which brings another argument, that horsepower is useless in drag and street racing. I say Bull... you need both equally.

I have a cheap drag prgram which is a nice baseline to figure out ET's. I inputted my information from Desktop Dyno (390HP and 390ft/lbs) into the program, in a 1988 GTA, and it did a 13.3 second 1/4 mile. Which is respectable if you ask me.

palric

iTrader: (1)

I did debate the issues for awhile. I think the no gas mileage thing just about sent me over the edge. Another argument was you won't be able to find a chip for it, etc. Most seemed to think you'd need a carb to run the rpms for the 302 which to me didn't make sense because with a few mods the TPI is more efficient at flowing air and delivering fuel.

Can your software perform a test like this:

- run a baseline to determine the 1/4 times with an LB9 305 TPI, 1.84/1.5 heads, cam (203/208 .431/.451), dual cats, 5-speed, 3.42, etc.

- run another test exchanging the block to 302ci and aftermarket heads to 2.02/1.6 keeping same factory TPI and cam, exhaust, etc. ?

That would be interesting because it would tell us what effect the new bore/stroke combo had in unison with the better breathing heads. The 305 is factory rated at 230hp and 300lbs torque.

RP.

Acceld Z

1 HP per cube using stock TPI componants? If you'd be interested, you can take my car for a spin at Grand Bend. I'm pretty sure I'm making more than 1 HP per cube. I have learned that those who bash TPI are the ones who either do not understand it and/or those who do not have it

darbleinad

hey johnyIROC,

i am interested in some LG4 stuff. what all you got? do you have a water pump? if you wanna get rid off the stuff i will take it.

palric

iTrader: (1)

The only hipo TPI I have driven was about 10+ years ago, an SLP'd Z28 which for a 305 was surprisingly fast.

If you read the BIG board it seems most people figure you have to go from TPI to a carb to make power ? That never did make sense to me. I suppose if you were trying to reach single digits in the 1/4 but otherwise I prefer EFI.

What do you think about the 302 thing Nathan and I have been discussing ? Eg: putting a 302 under the TPI ? In my case replacing the 305 with a different bore/stroke and large valve heads ? Have you ever heard of anyone doing this with a TPI ? Results ?

BTW: how is your 350 built (heads, rods, crank) ? Also, is the 355 (eg: johnyIROC) a different bore/stroke than a 350 or is it just a 350 bored over ?

RP.

johnyIROC

It's yours if you want it.... I'll take a pic of what I got left. Basically heads, block, an intake... old rods and pistons... and a crank. The crank has been bounced off of cement a few times....

I also have a set of stock 350 heads if anyone wants them. (I have ported dart heads now)

palric -> My 355 is just a 350 .030 over.

Acceld Z

I'm sure a 302 could be made to produce decent power levels since you are not limited on valve sizes as you are with a 305. But honestly, other than nostalgia or the desire to have something different..........why? I'm not trying to be an a s shole, I admit a 302 would be cool but more power could be made at more streetable RPMs using a 350.

nblanchard

I'd love to have a screamer SB chevy... and the 302 will make decent power... I am gonna go for it in a couple years

darbleinad

hey jonhy,

i will definetly take the stuff. thanks man.

trigger GTA

next time you are in rudys get them to show you the dyno # for the vet that they did up. 475 Hp out of a 350.

i should also have over 1 hp per cubic in.

palric

iTrader: (1)

Good question -- what price nostalgia ? Building a 302 will be more costly than building a 350. I figured I'd start by locating a decent 4 inch block, get it prepped and sometime between now and next winter decide if I really want a 302 that bad ? I can start looking for some heads after I find a block. The last choice as I see it will be the crankshaft. If I decide not to do the 302 then I can use the crank and rods from my 305 which makes the engine swap alot more affordable eh ? Well this isn't something I expect to finish this year and I am definitely not in a hurry either -- still lotsa life left in my 305 (the car has 70k on it).

By the sounds of it you've done some TPI/sbc buildups right ? Maybe you can comment on this -- I figure that if my 305 can make 300lbs torque and 230hp with small valves (1.84/1.5) and poor head design (lotsa shrouding as I read it), then changing the bore and stroke to 3x4 (to 302) won't cost me peak torque and because of the large valves (2.02/1.6) will take advantage of the cam and intake characteristics. This should show up as greater torque and greater hp numbers between 2000-6000rpm. I have never seen a 302TPI but do respect that the sbc will always make alot of power given a balanced setup (intake, cam, exhaust, etc). So to me gets down to this... the 305 is NOT a great peformance design yet it still moves my Firebird pretty well. The 302 is a much better design that should move my Firebird correspondingly better granted not as well as a 350.

I have 3 books by David Vizard that I have been burning the candlelight with. They are from the PowerPro Series, How to Build & Modify SBC V8 (1) Camshafts & Valvetrains, (2) Cylinder Heads and (3) Pistons, Rods and Crankshafts. I am trying to find a copy of the Chevrolet Small-Block V8 Inter-change manual. I used to have this but lost it. It really got into combinations that make HP and others that make torque (377 vs 383, etc). It had alot to say about the in-between motors (283/302/327). Fascinating stuff if you are into sbc's. Also, I have been trying to find info on the inter-change characteristics with the LS1 cranks and rods as well.

thx,
RP.

Acceld Z

One of the things I have learned is that TPI engines in general favour a longer stroke. It has something to do with the basic theory behind TPI that is called Inertial Supercharging. Another book you may want to consider is John Lingenfelter's book. I have it and I learned a great deal from it. The cylinder wall itself shrouds the valve on 305's not the chamber. I think a 302 would be cool just not very cost effective. I imagine a ported/siamesed TPI unit would be able to support the airflow demands of a 302. A solid roller cam would also probably best complement the 302. If it matters, GM created a 1997 Z28 with an LT-4 based 302 a few years ago. It was a monster. The cool part was that they managed to do it using GM parts. I have the article from Hot Rod if you'd like it.

palric

iTrader: (1)

Man if all I had to do was get siamesed runners that would be getting off easy -- I hope that is how it works out ?

I'd love to read the article on the 302. Please send it to palric@neptune.on.ca

thx,
RP.