Transmission for racing
Gunstar1
10-21-2004, 10:59 PM
I'm trying to decide which transmission to use in my 77 Firebird for drag racing.
What I currently have:
77 Firebird with a 305 2BBL and a TH350 transmission.
What I want to do:
The 305 is going to come out and be replaced by a Pontiac 400, 428, or 455.
I don't plan to go nuts with the engine, but I'd like to shoot for a low 13 second to high 12 second car. But I also want the car to be streetable.
What I'm thinking about is:
Getting a BOP TH350, but I don't think this will handle the torque of the big PMD engine.
Getting a BOP TH375, but I don't know much about this transmission. What is the good and the bad of this transmission? Is it a beefed up TH350, or is it a downgraded TH400?
Getting a BOP TH400. I know this will handle the torque, but it's bad for sucking down horsepower, passing a lower % through to the wheels.
Getting a TH200R4 (used in the Buick GN/GNX). I think this will hold up fairly well due to the fact that they are used on the GN and with a rebuild, may handle the torque of the big PMD. I may be wrong on this, though. The extra gear for cruising would help the mileage.
I'd like to avoid a lot of fabricating to use one of these transmissions.
Any suggestions?
What I currently have:
77 Firebird with a 305 2BBL and a TH350 transmission.
What I want to do:
The 305 is going to come out and be replaced by a Pontiac 400, 428, or 455.
I don't plan to go nuts with the engine, but I'd like to shoot for a low 13 second to high 12 second car. But I also want the car to be streetable.
What I'm thinking about is:
Getting a BOP TH350, but I don't think this will handle the torque of the big PMD engine.
Getting a BOP TH375, but I don't know much about this transmission. What is the good and the bad of this transmission? Is it a beefed up TH350, or is it a downgraded TH400?
Getting a BOP TH400. I know this will handle the torque, but it's bad for sucking down horsepower, passing a lower % through to the wheels.
Getting a TH200R4 (used in the Buick GN/GNX). I think this will hold up fairly well due to the fact that they are used on the GN and with a rebuild, may handle the torque of the big PMD. I may be wrong on this, though. The extra gear for cruising would help the mileage.
I'd like to avoid a lot of fabricating to use one of these transmissions.
Any suggestions?
FormulaLT1
10-22-2004, 06:40 AM
I think you should send Hypsi who's posted his GN in Member's ride a PM and ask him about the TH200R4. As for the Rest of them I haven't used any of the GM Auto tranny's Except for the 700R4 or 4L60-E . So I really wouldn't be any help to you.
John
John
Automotive Network, Inc., Copyright ©2026