305 to 400
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Joined: Jan 2000
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From: Tampa, Fl
305 to 400
Im building a 400sbc with stock pistons and rods. Im going to try to use my tbi for know and see how that goes. I have bigger inectors and I'm going to buy a spacer. Does anyone know what compression I would have with 72cc heads. Any cam, intake, head, header suggestions are greatly appreciated. Should I have anything done to the stock rods and pistons? Thanks.
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Joined: Nov 2001
Posts: 409
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From: Birmingham Mi, USA
your TBI intake will not fit onto the 400 heads. The 2 center bolts will be different, as they changed them in 86 or 87.
I suppose you can do it but you would have to drill them out.
I dont know about the cam, you can only go so radical without it effecting the computer.
Try calling Jet or Hypertech and see if they can make u a chip so u can go bigger on the cam side.
I suppose you can do it but you would have to drill them out.
I dont know about the cam, you can only go so radical without it effecting the computer.
Try calling Jet or Hypertech and see if they can make u a chip so u can go bigger on the cam side.
Joined: Mar 2000
Posts: 43,187
Likes: 42
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
Other than the difference with the center intake manifold bolts, the factory 400 heads are rotten for performance. If you go with replacement heads like World Torquers or Sportsman II's, you can get the proper bolt pattern and improve performance tremendously.
Then, your TBI is going to restrict things horribly. An aftermarket TB and intake will help that, though.
Next, you've got to address exhaust. Headers, 3" cat and cat-back are a must. SLP 1-3/4" primaries would be a nice choice for a mild 400.
Stock rods and pistons are fine until you get into the 6k rpm range or add NOX. ARP rod bolts are good insurance, even if you don't go wild on everything else.
You might try asking for more advice on the TBI board on how to make this combo work properly.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2200 stall TC. Ported World 305 heads, Crane PowerMax cam. ZZ4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster. 2.93 limited slip, Spohn SFCs. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, 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 @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
Then, your TBI is going to restrict things horribly. An aftermarket TB and intake will help that, though.
Next, you've got to address exhaust. Headers, 3" cat and cat-back are a must. SLP 1-3/4" primaries would be a nice choice for a mild 400.
Stock rods and pistons are fine until you get into the 6k rpm range or add NOX. ARP rod bolts are good insurance, even if you don't go wild on everything else.
You might try asking for more advice on the TBI board on how to make this combo work properly.
------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2200 stall TC. Ported World 305 heads, Crane PowerMax cam. ZZ4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster. 2.93 limited slip, Spohn SFCs. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, 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 @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).
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