Flatmilling EQ IMCA spec head

[dln383]

How much can I flatmill this head and still get the intake to fit properly. You guys already know this but it has to be no more than 10.5 to 1 . Gonna do one of the 500 cfm flat top engines for stockcar and could use some advise. I read that .085 mill would get ya about 61cc chamber but I don't have a clue. Thanks guys

[dirtracr5]

.080 will get you 62cc. if you dont zero deck the block (say 9.020) and get pistons with an added .020ch it will fit easy. .080 mill with a 9.000 it will fit but its not easy.

[Brian W]

Make sure you check the CC's of each chamber. I have seen them off by 2cc'c on the same out of the box head. 0.0055 per CC is the removal rate on the IMCA spec head. If they are off you can usually angle the head slightly from end to end (#1 to #7 cyl) to correct the chamber size. Also, and I'm sure you already know this but the shape of the valves you choose can vary greatly the CC of the chamber.

[dln383]

Appreciate you guys sharing the info. If I would mill .080 and deck at 9.020 would I have to use the .044 head gasket or would the .015 shim work ? My pistons are 1.560 CH so I'll be .020 down and a quench area of .064 with the composite gasket.

[Brian W]

Assuming a 4.030 bore and a flat top piston volume of -5cc. You could run a felpro 1094 .015 thick gasket and have .035 PTH clearance. Mill your head to 64cc and you will be @ 10.5 to 1. That will work but you are gonna have to check every cyl for deck height.