Tb 350 to tb400 swap, 72 lb c10???

[dukcaln]

So I am installing a motor that came with a very well built tci street fighter turbo 400. So I will be ditching the TB350. I have a 72 c10 long bed. What do I need to do and purchase to make the swap complete?

I was told I need to move the cross member back. Shouldnt my 72 already have the holes in the frame, since the TB 400 could have been an option?

Do I need to shorten the driveline?
Are the yoks different?

I would think that a c10/c20 of the same or similar year that had a factory TB 400 with a long bed would have the correct size drive shaft that would work in my swap, correct?

I called a local chevy gmc truck parts guy and he said he has a TB400 drive shaft from a same year or similar year truck that was long bed for $60, that should work right?

please any info would help, as my other option would be to use the TQ out of the TB 400 and just leave the TB 350 in the truck.

[john]

The th400 yoke is different than th350 yoke. driveline will be shorter. U joint might be larger size on the th400 if it came from bb truck.

[dukcaln]

ok, thanks, so it would be easier to get the driveshaft from a similar year c20 or so that had the TB400, swap ujoints and be done, is it that simple or am I missing something?

[clinebarger]

If the TH400 had a bolt-on yoke.....You will need a special "counter bored" slip yoke.

All '69 trucks with 3 speed auto's had TH400's.....Even 1/2 tons so a DS should be easy to find.

[dukcaln]

so I did find a DS from a long bed, complete two piece with everything... this seems like the best and simple way to go. everything else should be bolt on ready right...ujoints and such

[dukcaln]

ok after searching old threads I think I can move the cross member, get a complete 67-72 two piece drive line, the slip yoke and attach to my th400 (slip yoke shaft) I got and all will be good

anybody confirm?

[crazy longhorn]

Originally Posted by dukcaln

ok after searching old threads I think I can move the cross member, get a complete 67-72 two piece drive line, the slip yoke and attach to my th400 (slip yoke shaft) I got and all will be good

anybody confirm?

Its pretty much a "bolt in" , as mentioned. nobody really wants to talk about that D-shaft....for good reason! You will need an elect kick down (3 to 1 , on the shift)....she will shift down, 3 to 2 @ WOT without the eletric(3 to 1 only, on the elect, around 30 mph or less). Yes, the crossmember should slide back & flat azz bolt(assuming you are in factory sb spot, on the stands). As far as the D-shaft....thats a big bag of "worms"! There were 3 positions that the motor set....I 6, farthest to the rear. V8 sb, farthest to the front(3 1/2" diff tween the 2). The BB set in between those 2 spots....I will say about 1 " foward from the I 6 spot. As mentioned by Clinebarger, there were some bolt on yolks used on the trucks , with a 400 T....car trans was a slip yolk. My 69 longhorn had a slip yolk in the 400T....but after 240,000 miles ,I do not know it it was original! I do know that the mid to late 70's trucks that I played with, did indeed have the bolt on yolk on the trans To check this, just look at the end of the output shaft....if drilled & threaded,thats a truck trans. Hope that helps a bit.....crazyL

[dukcaln]

thanks, picked up the complete slip yoke and drive line along with carrier bearing from a 72 long bed that had a factory turbo 400.... pretty sure it will bolt right in.. thanks all

I have the electronic kick down that will attach to the throttle linkag at the carb...