my 340's heads on my 273????

Rob R said

I'd say the cr would be about 7-75 to 8-1 with a zero deck that big head gasket and a 74 cc chamber.

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CR is more than 9.0. Chambers on these "J" heads are 64.7 cc. They were cut .040 on the block and .038 on the intake side. 273's have higher compression than the poor 318. We even had to put open 318 heads on my brothers "67" 273 so we could run gas other than Premium.