New Idea for me.. Need some info

I know it has most likely been beat to death but what is the most backspace you can run on a stock wheel house 67-69 Barracuda? I thought I read somewhere that someone was running a 295 something... Sorry if there are typo's as I just had a shot in y eye a little while ago..

If I can run a 295 then that is what I will do and just stretch the stock wheel tubs and a spring relocating kit. This way the dana can be cut to stock length.