Is anybody 100% sure TH400's cases are interchangeable?

[243]

I really would like to swap in a smallblock chevy but I want to keep the quadratrac.

[Kenall]

iv done this very swap.

got me a AMC th400 and matching QT. removed the QT from the th400. dissasembled the th400, got the output shaft. got my matching GM th400 trany, took it to a local recommended trany shop, asked them to swap the output shafts and replace all seals and bushings inside while they were at it.

got a semi rebuilt and inspected GM th400 with QT output shaft back, bolted it to my SBCv8 mounted them in my wagoneer, and then bolted up the QT..boom...Gm 350, GM th400 and AMC QT xcase... :D

remember, the INTERNALS, are the only components that can be swapped between th400 cases. so no matter what xcase was bolted to a th400 be it an np205 203 208, dana 20 etc, the outputs shafts from those can be swapped into any other th400.

its the outside cases that are different and must be matched to the desired eng u want to use...olds th400 case to olds eng, buick to buick, and GM to GM...

[ August 02, 2001: Message edited by: Kenall ]

[243]

That is the best news I've heard since I bought my Wagoneer's...Thanks Ken!

[78WagLimited]

Ken.. Do the drive need any work for this swap?? I too am looking into the 350 swap.. my '78 already has the TH400..here in CA there are few if any performance parts legal for the 360..as you can imagine just about anything under the sun is legal for the 350's.. thanks for the info!! P.S. I was looking into the Advance Adapters swap and they wanted around $400.00 for the tranny adapter and motor mounts.. Thanks for the info.. :D

[78WagLimited]

OOPS!! I mean the drive SHAFTS... kinda left that out.. :rolleyes:

[Crazy_Jeepman]

You should be able to keep your driveshafts. I have done this swap as well and I was able to keep the drive shafts as the trans/tcase mount in the same place as it does now. I removed the front clip bolted up a SBC 400 to the TH400/Q-TRAC bolted it to the trans mount on the crossmember thus able to index the motor mount towers to the frame, with the front clip off this was a snap to do. Good Luck. ;)

[mark]

ken
are you saying that the output shaft from the chevy t-400 will definately not work with the q-track?

[jeepbob]

The output shaft from a chevy T400 will NOT work with a q/trac but the output shaft from a Q/trac t400 will go into a chevy T400 and work just fine. The short shaft chevy or BOPC t400 output shaft WILL work with a D20 and adaptor. I have a buddy with a Chevy pu with a T400 and we put the D20 set up in it so we share the same spare parts when wheelin.

[Kenall]

oops forgot...

243, if u still have the AMC tranny and the matching QT in the wag now, u can simply adapt a GM 350 to the AMC th400. AA sells this very item for about 300$.

ONLY A QT TH400 OUTPUT SHAFT WILL WORK WITH A QT.

IF THE TH400 IS INTALLED IN THE SAME LOCATION AS THE OLD UNIT. WHEN THE QT IS BOLTED UP, THE XCASE SHOOD NOT HAVE MOVED ENUFF TO REQUIRE NU DRIVESHAFTS...