A 5.0L is a 302. The 4.9L is a 300 6cyl.
Sure, you can drop in any ol' 302/5.0L, the block size is the same. If you want something a little bigger then stroke the 302 to a 347; you can't get anything taller without putting a bulge in the hood.
A small block was optional (302 c.i.) stock but these put out less than 175 horsepower! I have seen big blocks swapped in for drag raging (460 c.i.). A late model 5.0 will bolt in and would be a great ride!