Hi all... Looking for someone who's done this swap: I have a '63 Biscayne 2 door that originally was a 6 Cyl, 3 speed car. Stock drive shaft. I am putting a '70's 350 in it, and was wondering if a TH350 will interchange with the drive shaft, or if I need to source another one (shorter?) What about the splines, I assume (maybe incorrectly) that they are the same. I seem to remember that the TH350 was the same dimensionally as the PG and the 3 speed slushbox, but my memory is getting foggy here. Anyone done this swap?
should be a coarse spline yoke in it now. I dont remember if they had the short or long trans, I think it should be the long one so it would reach the trans crossmember. So you probably need to change the yoke, but not shorten the shaft (as long as you get a "short" fine spline yoke, not the "long" one)
i did my girls '61 bel air with a 6/pg. the front driveshaft needed to be shortened and the yoke changed. the th350 is the same from bellhousing to trans mount as the pg/3 spd, but the tail is slightly longer.
I did this 30 years ago, in a 63' Impala. If my memory serves me, I used the short tail shaft TH350. The shaft didn't have to be cut but I did have to make an extension for the trans mount. As mentioned earlyer, you will need the TH350 yoke.
The 2 speed automatics ( Turboglide and Powerglide) in '58-'64 X-frame Chevies are 1-1/2" shorter than short shaft TH350's, other short shaft PG's and 4 speeds so the driveshaft is longer. The 3-speed driveshaft will work with the TH350, IIRC the yoke is a different spline. If you can find a 4 speed driveshaft it is a direct fit with the short shaft TH350. I have owned 10 '62-'64 Impalas since 1973 so I've BTDT.
The Jalopy Journal
