I'll have to ask. He stopped by yesterday with the printout. Since I was there when he did the test I do know he used the same bore plate. Just for information the heads I put on the 273 had a bit more work than the heads he used for the comparrison test. My heads had a 70 degree bowl cut with a lot of blending and removing any sharp edges, removed sharp edges on int. and exh ports. Did a short turn radius cut around valve guides and a 30,45,60,70 degree cut on the intake valve (1.84) and a 15,45,60,79 on the exh. Used Ferra valves. Got 116% max velocity and they flowed 169.1 cfm at .500 of lift.