Comp Ratio someone confirm my numbers please

dgc333 said
-7.5 cc dome of a flat top piston is pretty typical of the size of the valve reliefs and adds volume above the piston and lowers the compression. Based on the numbers given the static compression ratio is 10.706:1.

NOTE: you will NOT have any quench with this setup. The 0.076 distance is just to large for it to be effective. For ideal quench you need 0.040 to 0.050.

You would be better off with a step dish piston with 15cc dish that you can zero deck and use an 0.040" thick head gasket. That will give you the same 10.7:1 compression and an ideal quench distance of 0.040".

Or, zero deck the pistons you have and use an 0.050" thick head gasket and you will be at 11.3:1 which is still well within reason for the cam you are using and the aluminum heads and still have an effective quench.

Dish would be better w/ zero deck but it sounds like he already has the pistons.... how did you get the 10.71 comp? i got that but put in Positive 7.5cc instead of negative. Negative gave it in the 12 range.
About detonation, some say 10:1 some say 11:1 w/ alum heads... Do you really want to have a motor that hot for the street. I have nothing against it and think it is awesome but reliability wise, unless, well it is your choice. all I know is don't waste your time adding octane boost to 93, add a gallon or 2 of 110.... then you can calculate your octane.... Hott Rodder or something did an article on octane boost and found it only helped 87 octane. With 91 octane it made less power than just straight 91. Food for Thought!