ok ski here is goes:
OE E7 heads have roughly 64cc chamber and the compression ratio is 8.80:1(advertised at 9.0:1 but not true)
shave the head .10"=62.4 cc and 8.96:1
.20"=60.92cc and 9.12:1
.25"=60.15cc and 9.2:1
.30"=59.38cc and 9.3:1
.35"=58.61cc and 9.37:1
.40"=57.84cc and 9.46:1
roughly each half point in compression increase equals roughly 15 horses. the max you can go on the E7 would be .40" and you dont have to cut the intake either if you go that high.
port out the exhaust roof and work the exhaust bowls. i was told to leave the intake alone, but if you wanted to, port match the intake.
sorry, no 10.5:1 for you unless you get different pistons.
also, ALWAYS check valve to piston clearence!!!!!!!
