Tranny Sizes

[Abishai]

I need as much info as any one can give me on new trannys.

What size will fit a 1977 Custom Deluxe cab.

I am looking for a 5 speed that I can bring up through the cab floor.

Where can I pick a new one up at?

Would I better finding a good used one?

Should I stay with my 3 on the Tree? (it has 98,467.9 Miles on it)
- How much more use could I get out of this?
- What would be best for highway use?

(I am going to be putting a 305 in it so if that helps any let me know anyother info you might need to help me.

Thanks

Stephen Newman