what heater and rad hoses do i need?

A-bodys use what are commonly called 19" and 22" radiators.
19's were used in /6 and 318 cars. 22's could be used in any of the A-bodys with A/C or heavy duty cooling.

Measure the width of the radiator opening .It will measure a little over 22".
People have put bigger radiators in,but you have to cut the radiator opening.