Transmission info/question

[gmiles]

I'm building a 74 Stepside C10 shortbed. I have a 305 for it and am looking for a TH400. I bought a 75 C20 long bed for a parts truck (the 74 was a recovered theft and stripped to the bones).  The 75 C20 was missing the eng/trans. My questions are:

Well, intially I had 6 or so questions, then realized I could condense them into one question.....What TH400 can I use to minimize the fuss? A long tail shaft slip on yoke, or a short shaft slip on yoke?
The C20 was a big block truck. I would like to avoid a bolt on yoke because I already have the 2 pc slip on yoke  driveshaft from the C20.  I don't have a problem using a TH350, but I think that would require another driveshaft as well. And cutting down the C20 driveshaft would cost less than another driveshaft.

[dumbucket1]

my 76 big block truck with the th400 has a bolt on yoke on the transmission....

[ccz145a]

My '75 big block truck has a th400 with a threaded output shaft and a yoke with no bolt. The trans is a rebuilt unit out of a 1 ton and works fine with the 1/2 ton yoke. It has the short shaft. It also has the deep 1 ton pan, which is nice.

[chevyguy5894]

What tranny you have currently? I had a manual 4 speed in mine and I used the front half drive shaft and TH400 with the bolt on yoke but it all depends on what you have if you have a short bed or a long bed.

[gmiles]

I don't have a trans yet. The driveshaft is from a C20 long bed that had a TH400. I want a TH400 but learned there was more than one version (long tailshaft/short tailshaft, slip on yolk,etc). Can the driveshaft be converted from a slip on yoke to a bolt on yoke? Any idea where to find just the bolt on yoke?