305 to a 400
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 705
Likes: 0
From: Peoria, IL
Car: 1985 Z-28
Engine: a big one
Transmission: 4 spd auto soon to be a 6 speed
305 to a 400
i have a 85 z28 and i was wondering if i could swap in a 400 into its place. i would like to use Fast Burn heads by gm, and i would also like to use as much stock components as possible, can i use the intake and those components. and how hard would it be to get a PROM for this setup?
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
The 400 is a very common swap. It is externally balanced, so you need the harmonic balancer and flex plate for a 400.
The Fastburn heads use the Vortec port arrangement, so your stock manifold will not work. Your stock q-jet and distributor would work on a Vortec q-jet manifold, however. The exhaust would be rather restrictive (is for a 305, for that matter), so 1-3/4" primary headers and 3" cat and on back would be best to let that engine breathe.
Chips are available to help your setup. Assume you have a carb now. About all it does is give a better ignition advance curve, from what I've heard.
------------------
82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, 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.
The Fastburn heads use the Vortec port arrangement, so your stock manifold will not work. Your stock q-jet and distributor would work on a Vortec q-jet manifold, however. The exhaust would be rather restrictive (is for a 305, for that matter), so 1-3/4" primary headers and 3" cat and on back would be best to let that engine breathe.
Chips are available to help your setup. Assume you have a carb now. About all it does is give a better ignition advance curve, from what I've heard.
------------------
82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, 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.
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 705
Likes: 0
From: Peoria, IL
Car: 1985 Z-28
Engine: a big one
Transmission: 4 spd auto soon to be a 6 speed
what is the difference between the vortech port confuguration and older port configuration? all i see is a difference in the center water hole, there is none in the fast burns and there is on older. what does this hole do. i also see that many intake manifolds will block off this hole all together. Any knowledge you have on this can help me very much.
This is my first project car and I don't know everything.
This is my first project car and I don't know everything.
Thread Starter
Senior Member
Joined: Oct 2000
Posts: 705
Likes: 0
From: Peoria, IL
Car: 1985 Z-28
Engine: a big one
Transmission: 4 spd auto soon to be a 6 speed
oh, I also remember this, the engine in the car right now is a 305 crate. Will the crate intake manifold, being newer, fit on the fast burn heads. Also other that replacing the injectors will I have to replace the runners to allow more air to flow into the 400?
Thread
Thread Starter
Forum
Replies
Last Post





