The only problem with the 307 crank for a 327 is the rebalance job blows the budget. (unless you can make the 327 pistons weight the same as the old 307 pistons, yourself.)
The 327 pistons dome is way too big unless you match it with a 76cc smog head.
For a 64cc head the 327 piston dome has to be .100" or less. (flat top) to be pump gas friendly.
The big dome +76cc head creates a very convoluted combustion chamber.
Last edited by F-BIRD'88; 03-24-2011 at 12:20 PM.