350 to 700r4 in truck originally 305/700r4 equipped

[erikgto]

Hi guys,

I just got my '82 Blazer that was originally a 305/700r4 3.08 equipped truck.
During the '90's this combo was replaced with a rebuild '70's 350/350 drivetrain.

I've found a 700r4 for sale out of an '87 G20 van.
What do i need to do and get to swap that 700r4 in my blazer, besides shorting my driveshaft.
Is my Blazer already equipped with the lock up or do i need a new kit?
Do I have to worry about my speedometer connecting to the tranny.

Anything else?

Any input is appreciated!