Will this work ????

I'm building a 70 dart... I bought a pile of stuff from a buddy who is getting older and winding down his hobby. I got a 1978 440/727 , and a set of 915 heads . I figured I would bolt on the closed chamber heads to up the compression.After I pulled down the 440 I see that the piston stops about 1/8 inch from the top. Now for the question ... Is this going to give me a weird quench and cause detonation? I realize that I will ony have 9.5:1 compression at best.This is my first mopar build, still learning .. Thanks, Chris