How "bad" are the cylinder heads you're dealing with? Cracks can be repaired, and valve seats and guides can also be changed. It might be simpler (and less expensive) to look into getting one of those heads reconditioned. It's also possible to machine the connecting rods for replacement bearings- - - - -I seem to remember that an Oldsmobile or Pontiac rod bearing can be adapted to the pre-216 rods.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!