This may be slightly off topic; sorry guys if it is--just let me know and redirect; I've got thick skin!--but on the subject of crank weights:
I'm looking at a '66 292 block, with the original crank. It's my understanding that the '64-66 292 cranks have six counterweights versus the 12 counterweights in later years, and are lighter than the later stock crankshafts.
Any reason not to stay with that crank in a non-race application? We're talking driving RPM (below 5000, generaly) and looking for longevity in the build. (It will replace the 250 in my 1969 Olds!)