10.5:1 273 pistons with 360 heads compression ??

I'm running 4.56 gears with a 4speed and a tunnel ram. I'm working on getting motor to wind up. I can't find any closed chambered heads and ended up with a set of 308 360 heads so I'm trying to make em work. My current heads are great heads but one has a small crack near the front of the motor. I don't think I'll need the bottom end power as much. With the gears a t-ram and light car this combo will like more rpm I'm sure.