If you decide to pull the heads and enlarge/measure the chambers, I have a good CC kit from Summit ($110 retail) I'm done with, and was planning to list on ePay. Say, $75 + shipping?

6 VOLTS/POS. GRD. NW INDIANA

Everything there sound really good.  We just got done on the dyno this morning and got 281 wheel horsepower out of it. We could only bring the timing up to 11-12 degrees before we had problems.  I am runnin E85 fuel but I think that our compression is getting in the way.  Especially with an old engineered cobustion chamber, I have no idea what is going on inside there.  I really think I am going to have to lower my compression. 

Bob is right in that some more info would be desirable.  You’ll need to cc the heads for an exact value but at this point, let’s assume you started out with un-milled G heads.  Assuming the heads had the advertised 69cc value and were then milled 0.020”, I get 65.92cc.  And you showed -0.002” for the decks which is 0.002” out of the hole.  If the value is 0.002” in the hole, then the static CR will be slightly lower (10.88:1).  The calculated static CR is quite high for even a normally aspirated engine on pump premium.  If some form of racing fuel is not being used, then keeping detonation at bay is going to be a real problem.

Lorena, Texas (South of Waco)

Probably some body here can/will but you needto give us some more info on engine parts. What cylinder heads, how far down the pistons are down in the hole,what head gaskets areon rhe engine? I believe Mummerts domed pistons are 10cc's so that will help in some of figering.

Seems to me some were on his web site he posted a chart to figure compression with verious combinations.

And I remember Ted posting somewere that .0006.5 milling =1cc reduction and 5cc's =1/2 point in comprestion increase (on "G" heads,maybe)???

hoppys1956

Hey everyone I was wondering if anyone could give me a hand on figuring my compression ratio.  There are calculators out there but I don't know my cylinder head cc or my piston dome volume.  I also am not sure of the head gasket bore diameter.  If anyone has this info that would be awesome, here is what is in my 1962 292 y-block.  I have Probe domed pistons from Mummert, 3.47 stroker kit, -.002 decked block, a total of .020 cut off the heads(don't know if any was machined before I bought them), my bore is .080 over stock and I bought the heads from mummert from a 57 292.  Any helpful info would be great.  Thankyou