Join Date: Nov 2010
Location: West Jefferson, Ohio
I recently did a similar swap in my shortbed C10 pickup. Yes I know, different application, but it should still apply here if you have a long tail th350 currently.
I removed my smallblock/th350 and replaced it with a garden variety 454/th400 from a truck. The th400 was a short tail and had a bolt-on yoke. Overall length was shorter than the 350. You can simply unbolt the yoke and use a slip style, but the stock driveshaft was too short and the yoke was too small. So I used a slip yoke from an 80's K10 with an np208 transfer case on my stock driveshaft. It's a longer yoke to make up the length difference and has the needed 32 splines. Also, since it was from a 1/2 ton, it didn't use a larger 1350 joint.
'69 Impala 4-door hardtop
'70 Impala Custom coupe