327 Buildup
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Junior Member
Joined: Jul 2001
Posts: 2
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From: Winona, MN, USA
327 Buildup
Last week, I threw a rod in my 89 Formula 305 TPI. I have a built 327 bored .030 sitting in my garage. I am going to drop the 327 in the firebird and use the 305 heads. The only reason I am keeping the heads is because I want to keep my TPI. I also want to eliminate some of the emmisions control devices to clean up the engine bay a little. Am I going to have major problems getting my computer to work with my combo? Next question is how wild of a cam should I go? I was thinking of the crane PowerMax in Summit for a modified 350 TPI. Will that work or no? Can anyone help me? I want to get my baby running.
Joined: Mar 2000
Posts: 43,187
Likes: 43
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Welcome aboard.
To start off, I wouldn't recommend 305 heads. They flow poorly and will raise compression quite a bit with their 58cc chambers. Although it will cost you a little more, get some Sportsman II's or something similar that are made for your 4" bore, have decent flow, and a chamber size more suitable for your engine. They are available with '87-later intake bolt pattern, have screw-in studs, can be ordered with springs to match your cam, etc. (you might want to verify you can get 64cc chamber with '87-later pattern). If nothing else, get their S/R Torquers, which are head & shoulders better than 305 heads for a 327. Even if you have to get '86-earlier intake bolt pattern heads, you can elongate the intake holes and get those center two bolts to match up. Please, for the sake of 327 lovers everywhere, don't settle for 305 heads!
Speaking of cam, you'll need to keep the cam operating range matched to the TPI operating range, meaning pick the pieces together (you'll need to get at least shorter runners to go above 5500 RPM).
The computer shouldn't have much trouble running the engine, although a custom chip or reprogram would probably help to optimize it. Don't go overboard eliminating emmissions control devices: About all there is that doesn't directly interface with the engine control is AIR, and although it might help in the "cleanup" department, it doesn't hurt you in the performance department.
Do your homework carefully, avoid the urge to "just get it running" and you'll be much happier with the results in the end.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 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/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
To start off, I wouldn't recommend 305 heads. They flow poorly and will raise compression quite a bit with their 58cc chambers. Although it will cost you a little more, get some Sportsman II's or something similar that are made for your 4" bore, have decent flow, and a chamber size more suitable for your engine. They are available with '87-later intake bolt pattern, have screw-in studs, can be ordered with springs to match your cam, etc. (you might want to verify you can get 64cc chamber with '87-later pattern). If nothing else, get their S/R Torquers, which are head & shoulders better than 305 heads for a 327. Even if you have to get '86-earlier intake bolt pattern heads, you can elongate the intake holes and get those center two bolts to match up. Please, for the sake of 327 lovers everywhere, don't settle for 305 heads!
Speaking of cam, you'll need to keep the cam operating range matched to the TPI operating range, meaning pick the pieces together (you'll need to get at least shorter runners to go above 5500 RPM).
The computer shouldn't have much trouble running the engine, although a custom chip or reprogram would probably help to optimize it. Don't go overboard eliminating emmissions control devices: About all there is that doesn't directly interface with the engine control is AIR, and although it might help in the "cleanup" department, it doesn't hurt you in the performance department.
Do your homework carefully, avoid the urge to "just get it running" and you'll be much happier with the results in the end.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 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/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
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