I could probably manage to do a 48" radius +/- a little, on my only lathe that's in operating shape right now. Anything that puts a slight crown on the lifter base would probably be sufficient, since very few of us are pushing these old engines to anywhere near their design limits.

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!