The Stovebolt Site Forums The Shop Area Engine Shop Swapping Trannies - 3spd to 4spd

I am about to swap out my original 3spd to a 4 spd. The 4spd is out of a late model and is shorter than my stock 3spd. My main consern is the tails. Can I swap the tails on the two so I don't have to lengthen my drive shaft? If anybody knows, i'd appreciate the help.

from input to output on any trans is specific to that trans, so not likely you could mix n match .... to take care of the driveshaft you might check the length of the one that was with the trans, could luck out, the spline on the front yoke will be different than your 65 anyway so you'll have work to do on the shaft regardless

Bill

Many Chevrolet transmissions have both long and short tailshafts. They are readily interchangeable, if you use all the same internal parts. This does not present any problems with using the shorter driveshaft with the longer tailshaft. I have done this interchange several times.

Thanks guys. After some talking and thinking I came to the conclusion to just lengthen the drive shaft. Evidently my dad has a lot of experience in the matter. You never know what a parent use to do back in "their day". Doesn't hurt that he's been a certified welder for over thirty years either. Thank anyway.

"The 4spd is out of a late model"

Do you mean a late model truck? If the 4 spd is from a '68 or newer truck it will be a SM465. If you didn't get it with the trans, you will need the bellhousing with larger hole for the bearing retainer.