i am gonna swap from 700r4 to the 400 turbo tranny to meet with the stock drive shaft what size tail shaft do i need? and how much hp do yous think a 10 bolt rear can hold under a 383 stroker 13.5.1 compression soo on.. about 600hp. machine shop said.. going by hear say.

what size tail shaft do i need to meet with stock drive shaft?

 

well i have heard that the 10 bolt can handle around 500 ft lbs and with you having an automatic tranny it will help but i doubt that rearend will last long with 600 hp and sticky tires....
I say drive it till it breaks then buy a moser!

sorry i dont know about the tailshaft.

 

The 400 uses a different yoke from your stock drive shaft. No 400 will accept it.

Face it, you're going to be doing some custom drive shaft work.... $75 plus parts, you're done. Big whoop. Not particularly painful at all; in fact, I'd rate it as one of the least things to be all bothered about in a swap of that sort; far cheaper than a converter or a good-quality rebuild, and alot easier than the crossmember issue.

 

There is a way to use a short tail TH400 with a stock TH350 length driveshaft and a slip yoke from a 60's Buick application, but you don't have an 82 f-body (with all production transmissions the same lenght as a short tail TH350,) so your driveshaft will need changed no matter what.