This weekend I set the engine and trans, 455/th400, into the engine bay to start figuring out mounts etc. in my '47 model 76. Couple of problems cropped up right away. First, my trans has the short output shaft/housing, and it looks like the U-joint would be too far forward and the driveshaft would move too far up and down where it passes through the X member. Appears the "medium" length housing/shaft will correct this problem. Also, I was using a later "stepped" GM driveshaft for mock-up, and the diameter is definately too big for the opening in the X member. I know there are several others on this forum that are, or have done similar swaps, and I was looking for comments or tips on these issues.
Thanks, Doug.

 

This sounds like an awesome project. You should post some pics.

 

Want me to crawl under my '53 88 and take some pictures? 425/TH400. I have no idea how the frame sizes match up between the two, but it might help...

 

Pat and Oldsguy have post WW2 40s Oldsmobiles with 455/TH400s. I recall that Oldsguy had to have the driveshaft modified quite a bit to fit the TH400.

 

My '46 has a long tail shaft TH400 and it fits. Maybe I can find a few photos or make some and post them. I had the driveshaft modified so it would fit the transmission on the front and the original 3rd member in the rear. I have a 9 inch on the garage floor that will go in someday......

 

Check photo #3 in post #51 and photo #2 in post #59 in this thread. They both show the relative position of the transmission to the frame/floor pan, kind of.....

 

Dan,
I find there are three lengths of th400 rear housings, the most common is about 9" long, and I think that will work the best. There is one thats about 13 1/4" long, but it is much less common, any idea what your's is?-can't tell from the pics. Mine is the short, 4 1/4", length, and it sure ain't gonna do it. Any pics anyone has would be welcomed.
Doug.

 

I have an Olds 350 in my '42 Chevy, I think they are similar from the cowl back. If pics of mine would help I can take some. I would love to see pics, these 40's GM cars are my favorite.

 

Doug,
Sorry I missed you question last week. I will measure the tailshaft and let you know but from memory I want to say 9 inches. I wasn't aware of the longer one, maybe used on trucks?

(you should have PM'd me, again sorry I missed it)