Hi Randy,
       I recommend taking out the rear seat if your heater core was leaking.
When I replaced mine last year, I found a ton of antifreeze lying around in
and under the carpet and padding (after all, the leaking fluid had to go
somewhere).  If you pull the seat (only 2 bolts on mine) you have room to
work and the ability to clean the area and reduce the nasty smell & rust.

Bill Marshall
'85 GL w/ Tiico power