Send me a PM and I'll respond with a phone number. it's easier to discuss the procedure in a 2-way conversation. The whole job takes less than an hour with a bare block to work with. After the modification the later model 56-63 mains will be a drop-in fit.
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!