'88 350 questions

[68chevystepside]

I have a 68 chevy stepside with an inline six that i am planning to swap out for a 350. i found one out of a '88 1500 which is what i want becuase it has a serpentine belt. i want to convert the 350 to carb, what else do i need to do besides changing the distributor and the intake manifold? will motor mounts from the 72 chevy c10 bolt up or will there be modification required? what will i need to have functioning power steering? will 72 chevy c10 parts work for that? would i be able to swap the pulley for the 72 p/s pump to work with the sepentine belt?? later on down the line i want to build this 350 to a 383 and i want to know what transmission would be better to go with, a 700R or the Turbo 400 and what year/ what vehicle do you guys recommend for the transmission. also will the stock rear diff be ok to use or should i replace that also?? if so out of what year/what vehicle? Thanks in advance.