I've usually been able to work the lifters up high enough in their bores to slip the cam out, and then use a wooden dowel and a hammer or a dead blow mallet to tap them out from the crankase. With the cam removed, they should also be able to go out the bottom of the bore. I've got a 216 block in the process of a bunch of oddball modifications, including having the lifter bores sleeved down to use AMC/MOPAR lifters. They're a few thousandths smaller diameter than stovebolt lifters, and a LOT less expensive.
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!