Originally Posted by Rotary Inspired

They are too thin on the faces to machine deeper champers to lower compression. The faces are thinner to save weight and allow a higher redline. I have yet to try and machine one down this is what I have heard from a couple folks who get to experiment a little more than me. I am lucky to do 5 or 6 motors a year due to time constraints. I doubt my 8 will get a turbo anytime soon as I seem to keep a turbo rx7 on hand all the time. If I were to turbo my 8 it would be w/ a cosmo motor of some sort 13b or 20b.