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OK, is your piston down in the hole .002"? or you took .002" off your decks so they are close to say .023" down in the hole now??

Then I will run it through the ROSS Racing Pistons compression ratio calculator for you. Then run it through the BOOST Calculator site to get to a Eff/D CR. number for you...

BUT I have a feeling you are too high compressioned unless you have aluminum heads????

I just ran it using a .039" hg, a 55 cc chamber head, a -4.86 cc valve notch flat-top piston and a down in the hole of .023" and you are at 10.99 to be exact!

You need at least a 63 cc head, imho to make right at 10 to 1 CR which will give you a Eff./D. CR. of 8.04 at 600 feet elevation like me or thereabouts with that cam so you can still use decent pump gas..

(I used 272/210/286/224, 110/106 and guessed at the lifts of .450"/.480" to get the intake valve closing point of 62 number!!).....

Get back..

Check me guys!!


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