15” wheel backspace on first Gen Camaro

[streetk14]

Does anyone know generally what kind of rear wheel backspacing will work on a first Gen F-body with 15” wheels and stock style suspension? I have 5.5” backspacing with my 17” wheels, but I suspect that would be an issue with shock clearance on a 15” wheel. I’m trying to figure out what I can get away with back there for a drag pack.

Thanks