I was going to use the Eddy RPM heads on my 493 and have them CNC'd. With the 440Source flattop piston I would have been in the 10.5 to 11.0 area. But I changed and went with the Indy EZ heads with smaller 75CC chambers. So I had to use the 440Source dished piston and I ended up with 10.6 having my pistons very close to zero deck as they came out about .006 down. My EZ heads are opened up to Max Wedge ports but I wanted that as I use a good size cam. Its a flat tappet custom grind from Dwayne Porter and it is 264 & 270 @ .050. With 1.6 rockers it has .624 & .630 lift with a 110 LSA. I have it in at 106 and I love the way it works and sounds. I just wanted to run 10's in my 63 thru the pipes on 92 pump and drive it to the track which it has as it has run 10.70's. I would shoot for a flattop piston at zero deck and you should be in the 10.8 area with 80 CC heads. Good luck , Ron