I have a 305 LB9 and despite people telling me it is not worth modifying i am going to do it anyway.I plan on adding SLP intake runners a,accel AFPR,SLP cam,Throtttle bodie airfoil and a new throttle bodie(what is the differnce between a 52mm and a 58mm and which will work better on my engine)I also want to add headers but are not sure which brand i also want to know who makes a good intake manifold i am also looking into bigger fuel injectors 30lb/hr and a cran fireball ignition i want to know if its worth changing my heads if so what will work best with these mods and other than the parts i have stated is there anything i have missed or different brands you would recommend any help would be appreciated.

 

The mods you are talking about are WAY over the needs of your 305. Let me talk you down a little bit.

1st, don't apologize for building a 305 - check the thread about tossing your 305 and getting a 350 on the Motor Swap board and you'll see my defense of that option. But, you have to be reasonable and get a "package" that will work, and what you're talking about will NOT work.

Start with the heads. Popular Hot Rodding (I think, might have been a different rag) did an article recently on a .030-over 305 TPI, making baseline dyno runs w/stock heads, then with World Products 305 heads. With no other mods, they picked up 50 hp. So, start with those heads, get springs to match the cam, have them pocket ported and gasket matched if you like. But, without them, most anything else you're talking about would be money down the drain. Vortec heads would be okay if the TPI manifold was available, but you'd need to get them shaved to keep your compression up and have them modified for screw-in rocker studs. Aluminum Vette heads would have the right chamber size, but neither the Vortec or Vette heads have the crossover passage for your EGR. So, I'd recommend sticking with the World 305 pieces.

Next, the 58mm TB is too big. The stock unit will be fine for a 305, or a 52mm for a heavily modified TPI. But, I'd seriously recommend trying the stock unit first.

Now, the cam, intake and runners all have to be designed to run the same RPM's. The SLP runners would be fine, although perhaps the port size is a bit large. Get an Edelbrock intake if you want, but keep the cam in the 5500 RPM redline range.

Injectors: 30 lb is WAY TOO BIG! Those are 434 monster mouse parts. Your stock 19's will be fine with the AFPR you're talking about getting. I know a guy who runs 19's on his heavily modified ZZ3 350, runs faster than when he had 24's in. Go ahead and get them cleaned and matched, but 24's would be a waste of money for you, let alone 30#ers.

Headers will help a 305, but only if the rest of the exhaust is upgraded as well. You could probably make 1-1/2" primary headers work, but 1-5/8" would be better for higher revs. Get a high-flowing y-pipe & cat, preferable 3", and at least 2-1/2" cat-back, 3" would be better.

Crane or MSD ignition (or a lot of others out there) will help your ignition keep up with all the other mods you're making.

The biggest thing you've missed is that you have to be reasonable about designing a package. Get your feet back on the ground, and you'll end up with a ride that will bring many smiles. Go down the path you were talking, and you're in for a bunch of frowns and bad words.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, Hooker headers & y-pipe, hi-flow cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

[This message has been edited by five7kid (edited February 01, 2001).]

 

Well stated Five7kid.

Also-Remove the screens in the MAF sensor, and work on a cold-air intake setup. This will help alot, even on a stock engine.

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Rob
'86 TA 305 TPI
Gutted MAF
Ported Plenum
TB Bypass

 

No emissions so no cat's and will removing the smog equipment hurt my performance.

 

nope.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Stay away from the S/R 305 heads.The exhaust flow is 139cmf @ 5000rpm.This is a BIG problem for me right now.Go with the vette heads(I wish I did).They flow better.Plus,
they are 40lbs. lighter.
Nitro Don

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1990 Trans Am WS6
305TPI 700R4

ENGINE:
150hp NOS kit
March underdrive pulleys
Edelbrock headers(JetHot)
Mac off-road pipe
Flowmaster exaust
Jacobs ultra coil
K&N filter
Fulley ported base,
runners,& plenum
Crane AFPR
Hypertech airfoil
Crane 1.6 rockers
210/220 .533/.544 Cam
W/P Torquer heads
Edelbrock TPI Base
Edelbrock TI Runners
Edelbrock 52mm T.B.
TRANSMISSION:
Richmond 3.73's
Auburn posi
B&M Mega shifter
B&M Transpak
Vette servo
B&M 2400 converter
TCI Trans Rebuild
Nitto Drag radials
FUTURE MODS:
The 700R4 is DEAD!!
Neeed to rebuild AGAIN!!
BEST RUN:
12.48 @ 109.23 MPH
(with stock heads,cam,intake,and crappy Pep Boy's tires)

 

Nitro, you're running some serious lift and a pretty healthy shot. I can see how you'd be limited by the heads. But, for a street driver, would that still be the case?

Again, problem with Vette heads is no exhaust cross-over, so no EGR - can be worked around, but what a hassle!

Tell you what, sell me your Worlds and you can go out and buy your Vette heads...

 

I have seen the cold air induction for the third gen camaros but the air filter is mounted in a different spot on the firebirds any hints on where i can mount mine I was thinking about getting a Throttle body mounted airfilter but heard that it would draw up hot air from the engine limiting it's effeciency and is there anyway to make the holes in my trans am's hood functional. thanks for the help i am going to end up saving alot of cash

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