I'm not sure how many people know this already or have received their edition of JP mag, but here's the scoop

Get a 2wd TH400 B.O.P. tranny (or GM if you're hard pressed to find a BOP :rolleyes: they're everywhere!) ; Take the Yolk and tailhousing off and buy your Atlas. IT BOLTS RIGHT UP WITHOUT EVEN A SPUD SHAFT!!!!

This is especially cool for Cadillac Guys since all Caddys came with TH400's This means no more BOP-to-GM adaptor plates for your tranny or swapping out tailshafts, or trying to get some $$$ custom adapter to get good gearing, or settling for the Marginally weaker (I know I've even said they would hold up and I still believe it) TH350 in order to have a decent set of X-fer case options.

Anyway I thought some people might be interested in this information.:smokin:

And which of the three tailshaft lengths does it fit?

Since the majority of Cad-sourced THM 400s are long tailshaft models.

Doc.

It will fit any tailshaft cuz it bolts to the tranny in the same place that the tailshaft does. It won't fit the cadillac car trannies though because they don't have the right output shaft. At least the 2 that I have sitting in the shop don't. IIRC you have to use the th400 with a bolt on yoke not a slip yoke. Of course this output shaft could be readily swapped into the cad tranny. LAter

That is correct you must have the bolt-on yolk. And I'm not sure how many caddy trannies came with that. Oh well it was fun to believe while it lasted. So you could either just buy an adapter for the BOP-to-GM bolt pattern (appx $150.00) and run a reg GM TH400 or swap out the mainshafts........SIGH*

Maybe I should call AA for more info.:usa:

little bit of junkyard-fu for ya:

69-71 jeep wagoneers and pickups used the buick 350 coupled to a th400 which was bolted onto a dana 20. the 400 was a GM bolt pattern with a BOP/GM adapter ring and the d20 has an adapter to the 400 as well. both these adapter are really damn rare, as you can guess. i'm gettin ready to swap one of these drivetrains into my cherry pretty soon actually...

anyway, i hope that helps. i hear the caddy 500s are monsters