Hey, I know this has probably been gone over 1,000 times before, but I couldnt find a straight answer, just a lot of bashing. Therefore, before I start this, I would just like to make one thing clear. I do NOT want to go with a 350!

There, with that said, here's what the car has so far.

'89 Trans Am
305 TPI
Originally auto, converted to t-5
3" Flowmaster catback
3.73 Richmond gears w/ Auburn posi
Other than that, all stock as far as I know.

I don't want to go crazy with this motor, just beef it up a little bit. Run with stock LT1's. Maybe high 13's.

I'm thinking a decent cam, heads, headers and CAI should give it a big improvement.

Oh, and any estimates on what the car should be running right now? 15's? Just so I know what I'm starting with.

 

I ran a 305 with a 08-302-8 comp cam and it made about an 214 at the rear wheels. That was with a stock TPI on top of it.

DavidT from Thunder Racing had a stout 305 that was running 13s I think. I also 'think' that that was NA. He was in the 12s on juice.

I would recommend the above cam and possibly the World Products 305 heads or maybe the Vette heads. I'm not sure if anyone has ever looked at 305 vortec heads. Not sure if they flow very well or not.

I did alot of bolt ons to my 305 to get into the 15s with my stock car. Although it was heavy....I'd say upper 15s is the best you'd probably run...

 

Look at my sig. also do a search for the following guys

TunedPort335
mw66nova
TimBurgess
Willie
SittingBull
Wishmaster (or something like that, he has a white iroc)

 

woah wait a minute, i may be wrong, but im pretty damn sure a stock tuned port 305 is already in the 15's if not high 14's by a good driver.

 

Not if its an automatic

 

My IROC came iwth the Anemic 305 automatic cam from 87. 190 hp of screaming fury. Some of you probably have the 235 hp 305s from later years. Couple that with a T5 and you have a whole other car!

When I bought mine, it would do about 16.25s. I had a grandma on a walker pass me at the 1/8 one time.

 

That makes me feel a lot better

 

The 190 hp cam or the old lady?

 

that I could probably compete with the old lady...



beside that, on the street I don't think that the difference is that big. Sure I kicked my friends *** when he wanted to know how fast his 170hp TBI is

 

So, what you guys are saying, is that the only thing that differentiates the 305 (190HP) in my car from the 225 HP 305 is the cam? Switch the cam out for a bigger one and I should be able to hold my own against stock thirdgen 350's?

I've always heard that the g92 305TPI 5 speed cars and the 350's were almost evenly matched, with the 350 fairing a little bit better, but it would be a good race. So like I said, switch the cam, and I should be able to pull ahead of a STOCK thirdgen with a 350.

Switch the heads, ad headers and from what I believe, I think I'll be able to hang with the slower LT1's (auto, 2.73's) Am I correct in thinking that?

Oh, and don't tell me to swap to a 350 is I'm already gonna be changing the cam, etc. Won't happen, but yes, I know it is the better way to go.

 

Three-fifty Schmee-fifty! J/K


First run it at the track and see what your times are. I'm betting those 3.73's aren't helping you right now. Stock TPI cars have a severe case of asthma above 4500rprms. This is where 3.73's like to be. W/o the breathing room, your making your topend even worse.

So with that said, get some SLP runners, edelbrock base (or port the base as much as possible and semi-siamese the base), home gasket match the runners, and port the plenum. That should help you out a bit more up top, but if you want more you'll. I think that will be my plan of attack as well.

While that base is off, you might as well look into a bigger cam & better flowing heads. If your car was auto, then you had the peanut cam. Look for an Lt1 cam and some heads. I'm interested in some 88-91 Aluminum vette heads. I'd port those suckers and throw them on my 5.0 with some higher rate springs. Then get some headers and a ECM tune and you should be spanking LT1's.

I hope that helps. Good luck!!!!

 

Showing my ignorance here a little bit - I always thought any 350 heads were a bad idea on a 305 so, why have a few of you guys mentioned the 'vette aluminum heads? Do they have a different valve layout in the coubustion chamber that makes 'em work on a 305?

Also, just a note about the later years 305/T5 combo - just by the seat of the pants, my IROC pulls pretty good. I think '89 IROCs with the 305 and a T5 had the best cam through the 3rd gen years, across the board, but I could be mistaken. Don't have much to compare the car to, other than my SVT Focus (in storage now), but then they are really hard to compare anyway - each is totally their own beast. For one, the SVTf pulls hard to 7200 where the IROC would belch connecting rods, valves and piston parts past 6000 probably...... Many, many other things about them are drastically different......

Anyway - still curious about the 'vette heads thing - wasn't aware any 350 heads would work.

Kev

 

First of, pretty sure I mentioned this, but the car was originally an auto, so I'm guessing it's got the peanut cam.

With that said, just like to point out, I believe the SD (91/92) cars with the 305/5 speeds all had the same cam as the 350 regardless of G92 or not, right? Because, Seat of the pants wise, this car doesn't seem at all slower than my 91 z28 vert was, that came stock with a 5speed. They seem pretty much the same.

I'm not gonna be running the car anytime soon though, so no idea about times

 

Vette heads have 58mm combustion chambers, just like the 305 heads. I believe the regular L98 heads have a 63mm or something like that. They work too, but decrease compression ratio, to what I don't know. But, the al. vette heads don't have an external EGR provision for those that want to stay emissions legal.

No, ALL SD cars got the L98 cam. My stock car is auto and puts down 190whp, there is no way that would happen with the peanut cam. Also, people have removed their cams from auto/SD cars and they are infact L98 cams.

 

The Peanut Cam went away in 88 or 89...

You probably have a 215 hp engine

 

BigWhiteGTP, I think you mean 58cc not 58mm. The combustion chamber on the aluminum 'vette heads is 58 cubic centimeters, which is a measure of volume. These are great heads for a 305. they have smaller ports to keep velocity high, and they have a very good exhaust port. I have them on my 305 and they made a big difference in power over the stock iron ones. there are many people that have had great results porting iron 305 heads.

 

No wonder that didn't look right when I wrote it.

 

Don't mind me if I avoid the whole cam debate, and just answer the question.

Here's how I would do it.

Cam: 214/220 - .480 or better lift on each side, agressive high ramp lift speed - LSA 112 or 114 to keep the ECM sain.

Accel Base, Accel LTR's (not superram, but that is an option)

Headman Longtube Headers, dual 2.5 inch exhaust, ditch the single pipe ASAP. (I won't listen to crying about this, think whatever you want, duals win races.)

World Torquer 305 heads.

Centerforce DA Clutch.

3.42 rear gear

MSD6al Ignition

Easily a 300HP crank combo if your shortblock is in fair enough condition, and easily into the high 13's. Also, keeps you emissions legal, and power below 5500 RPM, with a good solid chunk of it between 2600 and 5200 RPM.


Also, something to think about - if you really wanted to go at it, jump right into the super ram (HARK! Super Ram on a 305, yes - shut up and listen.) because it will allow for greater VE around 4500+ w a 305. That's the same range as an LS1 intake, so what's so wrong wih that? If you did that, switch the cam to a grind about 218/226 with the same lift, and hold to holy hell on. The exhaust will be in place to support it, and the heads will begin to run out of breathing room up top, but not so much that it's worth spending big bucks on them. As a 5spd car, you will lose low end, but is it really that important if you can launch at 3000 RPM and keep the engine in the ideal powerband? With a combo like that, 300 HP at the rear wheels is more like it, with low mid 13's in the future. You could also keep the 3.73's.

Small bore... who care's, you get the benefit of small chambers as well. And let the whining begin about high RPM 305's.....

 

"I've always heard that the g92 305TPI 5 speed cars and the 350's were almost evenly matched, with the 350 fairing a little bit better, but it would be a good race. So like I said, switch the cam, and I should be able to pull ahead of a STOCK thirdgen with a 350. "

My first '91 was a G92 305 T-5.
It was a freak.
Bone stock it killed my friends '91 350 that had a few minor mods.
Still stock with around 7-10k miles, it went 14.57 @ 90.821mph at the old Bristol Dragway. (best run)

 

Not a freak. I had a '91 Formula stick that behaved weird from the day I got it. First run I did was 14.51 I forget the mph. And that was on garbage Multec injectors. I new a guy had a '91 Z28 with exact same setup 305/t-5 but he did 14.48 stock.

 

the auto cars still rated 20hp less than the manual cars, and i think that has to do with the cam or something

 

85 305 LB9 had a decent cam. The 86 and up 305 Autos had all the peanut cams i believe

 

Just cam it, a zz4 sound put you around 250hp.
something larger than that would do you better. But you have to change the multec injectors, even for 24lb. injectors and (modify the prom?).

the 24lbs. injectors will take you up to 300hp. Your stock ones 19lb.= 240hp.

If you want a decently fast 305, cam it, have the heads machined to remove the valve shrouding, headers, exhaust, and fuel injectors. The stock intake is all your car needs. The airbox flows around 500cfm, anf the stock tb 600cfm and change.

 

oh yes if you just want to keep up with L98's, the zz4 is around $100 brand new. Just look in the for sale sections

 

What year corvette heads fit the 305. Also are they a direct bolt on or is there modifications that need to be done?

Regards

 

I hope to be putting up some good numbers on the dyno soon. Going to get it done hopefully.

 

your 87 was a pig sorry, my 87 car with a cutout went 9.7 1/8 mile and 15.2 or 15.3 in the 1/4

 

What im doing with my 305 TPI is as follows:

Holley SR (If I can find a way to get through emmissions) - $500
Vette Alum Heads with a port and polish job - $??
Comp Cams Cam #K-08-306-8 : 2k-6k RPM | Int Dur @ .050 - 230 | EXH Dur @ .050 - 244 | INT Lift W/ 1.5 - .510 | EXH Lift W/ 1.5 - .540 | LSA 112* - $700
Comp Cams Alum 1.6 RR - $150
Comp Cams Chromemoly Pushrods - $130
Powerhouse 335 Stroker Kit - $700
Hooker Super Competition Emssions Legal Headers - $400
Flowmaster American Thunder 3" Dual Exhaust - $300
------------------------------------------------------------------------------------
So for around $3k give or take you could have a fairly potent 305. You could save some money by keeping the stock TPI and just having it ported and what not, also just by porting the stock iron heads instead of buying alum and then porting them also.

 

That some good stuff there. That what i plan on doing to my 305 also. To stroke it, all you need is that kit from powerhouse, right? Also, where could if find those L98 Alum. vette heads? If i was to get my heads ported, what specs. would i have to get them ported to? I'm still trying to understand cam talk, still alittle bit foreign(sp) to me.

 

Your engine will be a pig around town. Might turn some 'decent' peak numbers, but it will have almost no torque around town and won't be fun to drive.

That cam is way too big for a 350, let alone a 305 or even a 335.

Be prepared to be disappointed IMHO...

 

Was that bone stock? Was it with the T5?

I'm guessing you mgiht have a T5 and the 215 hp cam that came optional with them...that would probably get you there.

That or you had good traction and an optimum altitude to run at.

 

Ok, my 305 tpi car runs low 13's with abit of stuff done to it. I have full 3 inch exhaust from the collector to the tailpipe, edelbrock aftermarket headers, ported heads. I am running the t5 transmission with 3.42 rear gears, and running 245/50r16's all the way around. The motor still has stock block, heads,cam, manifold, runners, plenuim. The car has lots of low end torque and gets up to speed no problem. my car is an 88 firebird formula L98 car, 305 tpi. this is just a thought for you guys who want more power out of your 305ci.

 

L98 305?

You mean Lb9, right?

 

87TA,
That is too much cam for a 305. You should really re-think that....

 

Gee, that's funny.

I also have an 88 Formula, with the T5, BW rear (3.45), Hooker headers, Edelbrock batback, stock internals, and 70,000 miles. I'm in the mid/low 14's. Basic head porting of the stock casting gave you a full second (or more) advantage?? Hummm

 

i am running 3inch dnyomax catback exhaust, the heads are ported but nothing to extreme. i forgot to put in my last post a few things i forgot, i also run a centerforce clutch, an air foil which doesn't do much for a power adder.

 

Sig has whats been done to put my N/A 305 TPI running 13.90's consistantly.

 

Same Dual friction clutch here.... I really need to do some head porting I think if that's all you did to run low 13's....

What do you call low 13's and at what trap speed and atl/temp?

 

i run about 13.20's at about 100mph, the temp is about 100

 

a stroker kit would defeat the purpose of the thread starter ..



http://www.hioutput.com/tech/343hp/343hp.html
http://www.hioutput.com/tech/400hp/400hp.html

or you can beef up the internals and SC it ..

 

You could always go with the L69 heads as well and that should raise the compression up from ~8.5 to ~9.5 on a stock 305 block. I think the regualr 305 heads are actually around 72cc or 68cc? I know the L69 Heads are like a 58cc head

 

I'm pretty sure stock TPI compression is 9.5:1 and the difference in L69 heads and Lb9 heads is angle bolt pattern and not much else.

 

Was she on nitrous?

That's about the same as my stock LB9 - 16.08 is about the best I can recall, stock everything. It still has the original front tires.

 

ah ok. forgot to actually look at the year of the cars. so that was my bad. I was was in my carb thinking mode since all my camaros came with one.

 

I've got the 235 HP 1987 305 TPI with a T5 and it is really fun to drive!

Soon it will be back together with SR Heads and an even better cam. I can't wait to see how she runs then!

 

HUH? N10 (Dual cat) wasn't avaliable until 89. Do you mean 215 or 220HP?

 

You're right, my mistake. It's not a dual cat, just a single exhaust. So I think that make s it a 225 HP.

 

Chrisamero, you are a fool. no one runs bottom 13s on a 305 with just exhaust and ported heads, heck you would barely run 14.2 with just exhaust and "ported" heads. Unless you can somehow prove your car actually ran a 13.2 quit posting garbage.

 

My bone stock '84 L69 car would run 14.50's all day long. Before
I got serious, I put an Edlebrock Performer, Holley 600 vacuum
secondary, a brand-new, but stock hei, Moroso wires, a Holley
hi-volume fuel pump and a set of Hooker headers with true dual
exhaust. Other than that, I had Centerline Auto/Drag 15" x 8"'s
and BFG Comp T/A's and a stocker 5-speed. It would run 13.20's
with that set-up.

 

M. Hall, "would" or "did" run 13.20s Did the car you are referring to actually run bottom 13s or are you just speculating that it does or that it should have.

M. Hall i think you are as full of it as our friend Chrisamero. No one runs low 13s with a 305 that has stock heads, cam, and displacement on street tires. What you are saying is that your stock displacement 305 with stock heads, and stock cam is making 330 horsepower? How come neither of you posted any trap speed?

Lets get back to reality here, you guys need to stop spreading this crap around. Unless you guys can prove that your cars actually ran low 13s, quit posting garbage. You guys are the armpit of Thirdgen owners.