The exhaust valve is moved .050 towards the wall to allow a .100 larger intake. Center punch the piston down the guide at 10 degrees before or after. Use a compass to sweep the reliefs you have to see where you are at. Set compass at half valve size. If you have B-1 pistons in it you may not have to do much to the reliefs if the piston manufacturer was a little generious with his cutter. Frank