cometics to lower compression?

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May 28, 2001
I lost my cc numbers on my head, but it is at close to 9.5 to 1 compression. I am switching from Loc-Wires to Cometics and figured I would thicken them up to get the compression down a little bit. After I shave the heads down .010 to get rid of the loc-wire grooves I figure I will need to add at least .030 to the head gaskets to get the ratio down to a more liveable 9 to 1. So will .060 compressed Cometics get me where I want? I/m running a 274 inch stage 2 with Stage 2 heads on a 4.020 bore and 3.59 crank.
Greg Kring
 
Greg you may know this but run as thin a gasket as you possibly can....Easier to push a thicker gasket out. Aren't 1007 locwires around .042 thick? I'm running .057 Cometics in mine, 14 bolted. So far so good....Scott
 
I did some playing around using this compression calculator. If we guess that your chambers are maybe 40 ccs, this gives a 18cc dish with a .042 locwire gasket and zero deck height to get 9.46:1 compression. Going to an .057 gasket, with no other changes, drops compression to 9.00:1. Figure that you'll lose at least a couple of ccs off of the heads when you take the grooves out; a 38 cc dish would end up with 9:24:1.
 
Hrm...Thx Kendall, that may come in handy. I'd also check piston to valve clearance before I buttoned it up.....
 
You're also going to put the intake ports farther away from the intake flange.
 
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