TH400 Swap
Thread Starter
Junior Member
Joined: Aug 2016
Posts: 9
Likes: 0
Car: 1989 Firebird Formula
Engine: Chevy 383 ProFlow XT fuel injection
Transmission: TH400
Axle/Gears: 3.73
TH400 Swap
Hi,
I recently blew my 700r4 and decided to throw in my TH400 that I had lying around. It’s a 72 long tail TH400 that came out of a Pontiac. I was wondering which torque arms and crossmembers will work with the long tail? Thanks in advance.
p.s. I already know I’ll need a adapter plate to bolt the engine to the trans. I got a Pontiac Trans because I’m doing a Pontiac 400 swap in the next couple of months
I recently blew my 700r4 and decided to throw in my TH400 that I had lying around. It’s a 72 long tail TH400 that came out of a Pontiac. I was wondering which torque arms and crossmembers will work with the long tail? Thanks in advance.
p.s. I already know I’ll need a adapter plate to bolt the engine to the trans. I got a Pontiac Trans because I’m doing a Pontiac 400 swap in the next couple of months
Joined: Aug 2006
Posts: 12,804
Likes: 103
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: TH400 Swap
I don't believe any will work with a long tail. You will probably have to modify one or build your own.
Member
Joined: Mar 2014
Posts: 140
Likes: 0
From: PA
Car: 87 Camaro LT
Engine: 383 Twin Turbo - In progress
Axle/Gears: 3.43
Re: TH400 Swap
As stated before, there are no commercialy available kits for a long tail TH400. You'll need to swap the tail housing and output shaft to a short tail one.
If you do decide to swap the tail housing and shaft I'd suggest a full rebuild while the transmission is torn apart and doing the dual feed mod to it. Depending on the HP you want to make, you can do other mods but the dual feed is a very simple and easy modification that costs maybe one dollar for the cup plug. But you need to have the transmission apart to perform it too.
Outside of that, I'd recommend a UMI crossmember and torque arm setup. Mine was a direct bolt in and fit wonderful. Plus it tucks very nicely under the car.
~Mike
If you do decide to swap the tail housing and shaft I'd suggest a full rebuild while the transmission is torn apart and doing the dual feed mod to it. Depending on the HP you want to make, you can do other mods but the dual feed is a very simple and easy modification that costs maybe one dollar for the cup plug. But you need to have the transmission apart to perform it too.
Outside of that, I'd recommend a UMI crossmember and torque arm setup. Mine was a direct bolt in and fit wonderful. Plus it tucks very nicely under the car.
~Mike