I'm not sure if anyone has covered this question. I have an original 69 440 magnum factory pistons, etc. (Grandmas 69 Charger R/T) If I pulled the 906 heads off and put 440 source heads, on would there be any valve to piston problems, large compression ratio changes, or other issues. I was considering this for the weight savings, factory look, and a bit more hp. I have a mopar m1 factory style alum. manifold also. Has anyone done this?