driveshaft info 350/th400

[mookandairin]

hi all, I am not sure if I introduced myself or not but I am Dan. Ppl call me Soda. I am building a 64 stepside with a twin turbo, intercooled 355 give me aprox 800 HP @ 15# of boost. I got the mock up motor in there and the th400 what I need is a little info like how long of a shaft do I need or what can I take one out of? I got a slip yolk out of a th400 already and a shaft out of a 92(?) stepside that had a 4L60E is the thing in the ballpark or should I just get one and do it the hard way lol ( it seems everything is the hard way these days ). I been working on the wiring for about a week or so and got all the melted crap replaced and working ( the guy before me had no clue how to wire a thing and shorted out the whole thing ) The truck is made from several other trucks from all over the country and it has gmc harnesses to chevy harnesses ect ect. and from several years hence taking a while to fig it out ( colors didnt jive exactly ) so I had to use several diagrams lol. anyways a little help on driveshaft length would save a bit of time ya know.Thanks for all your help.

this is the motor going into the truck. It is sitting in my old project a 60 studebaker Lark. although the Lark never got finished due to the build list never getting shorter the motor is where the heart and sole is to any vehicle and it will rest upon a 64 chevy truck C10

as you can see I got a good project on my hands and it is real far. it has the disc brake conversion in the front ect ect. lmk what you all think about this one.

I will post more pix as I get more done. I hope you all like it
and this is me.