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i am planning a head swap (windsor jr,gt40p,or thumper e7)in the next month and need /want more compression.right now i do not know the values for the calculator provided here other than bore x stroke.i believe the easiest ways for me to affect compression in the comming tear down is milling the heads and head gasket choice.how much millig is safe and how thin a head gasket can i use.the other info you may need is that i woul like to use 1.7 roller tip rockers
 

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I use a ROL head gasket that is .039 compressed. Fel-Pro I believe is either .040 or .042.

You'll also need to know the combustion chamber size of the head along with the piston type and deck clearance.

As far as head milling, it kind of depends on the head you choose how much will need to be milled. I don't have any experience with the heads you've mentioned but I'm sure someone else does.
 

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Not sure about the E7s but most of the GT-40 types lose 1 cc for every .006 taken off. YMMV. All the normal gaskets figure about .040 thick. You should zero deck the engine, use the .040 gaskets to set the quench distance and then pick or modify the heads to get the compression ratio you want. You can buy $100 a pop Cometics @ about .020, but if/when the pistons hit the heads it might seem like money wasted.
 
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