TH400 question

I think I want to do a drivetrain swap. Now I can get a TH400/dana 20 package for free from a buddy. It's from a jeep originally. I have a 350 sbc right now. From what I've read it should have a AMC bellhousing but some have earlier models had an adapter to go on a buick 350. I haven't seen it yet (never look a gift horse in the mouth) I am just curious what problems I will have to deal with if I try and go this route. I know very little about this and am new to the world of wrenching and swaps and stuff.

 

T400 in a Jeep could be the AMC bolt pattern or the Buick bolt pattern, but neither will bolt to a Chevy V8. If it's the Buick pattern you can get an adapter to the Chevy. Have you looked at the length of this setup? TH400 is pretty big for a short wheelbase Jeep.

 

Very difficult to do with a v8. There simply isn't enough length to the vehicle. I have done it just to prove that it is possible, BUT the rear driveline was only 9" long. It is a very good swap behind a v6 however. I have been running them for years as they bolt right up to Buick v6's. Still an inexpensive way to put a auto in a short Jeep. One other real drawback is milage. The wife's Jeep gets 10 mpg with the 400 turbo and my 71 gets almost 20 with the t-98. Everything else is very close drivetrain wise.

 

Before around 1973, the TH400 used in Jeeps was the Buick nailhead pattern (a shorter case) with an adapter ring. The adapter ring allowed use of the various engines (225 and 350 Buick, AMC engines) by use of the appropriate ring. After about 1973, Jeep started sourcing TH400s with AMC-patterned case, dispensing with the nailhead/ring strategy.

The best (and cheapest) route to adapt a Jeep TH400 to a Chevy is to find a Chevy TH400 and transfer the Jeep TH400 tailshaft and D20 adapter to the Chevy TH400. This requires complete disassembly of the transmission (the tailshaft is the last thing to come out), but it will bolt up to your SBC and D20 just like it came from the factory that way. You can do the same with a BOP TH400, and bolt up to any GM BOP engine too.

Re putting the TH400 into a flatty, I've seen it done with a V6, but they had to scoot the engine forward to make enough space for the long drivetrain. With a V8, I expect you will struggle to make enough distance for the rear driveshaft.

 

k thx for the input. Sounds like this is beyond me ... for now.