Be sure the newer block is drilled end to end through the lifter bores to supply oil to the lifters. Early passenger car 235's with Powerglide transmissions had blocks drilled for hydraulics- - - - -standard shift cars and truck engines were not drilled for hydraulic lifter oiling.
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!