Need some help figuring CR

moparshwick94 said
So this is the problem here, especially with the Summit Calc, it gives me the lowest CR equation out of them all. Gives me an 8.3:1, and when using original cast flats, same compressed head gasket, and losing just a hair of material by resurfacing decks and heads, the CR numbers should be at stock, or even a slight bit higher...and that's going based off of factory CR at 9.5:1...so I'm confused..

Factory compression ratios were bs for the most part. Ignore that in my opinion as alot of motors had the pistons much further down in the hole than the "blueprint" number. If your numbers are correct, that calc will be close. The other calcs simply take more data to "tighten" up the calc. I would guess thou it'd be less than 0.2 of a point.