Given two bad choices use the 302 heads, they are closed chamber so you could use quench pistons with them. Both the 84 heads and the later 302 will have smaller (273-318) intake ports and either will be a bottle neck in 360's breathing without a lot of porting work.

Yes, a hydraulic roller in an 84 360 block will be just as expensive as a big block.

Since you are interested in better heads and a roller cam, have you looked into finding a 5.9 magnum engine? Good flowing closed chamber heads, less expensive roller cam option since the factory roller parts work fine for all but high rev engines.