The simple fix for a 216 with a worn bore is to use aluminum pistons for a 235. It's a 1/16" overbore (.0625") with the same wrist pin diameter and compression height as a 216. There are plenty of standard bore 235 pistons available at reasonable prices- - - -check Ebay. The engine ends up at 224 cubic inches, has a little more compression, and the aluminum pistons don't wear out the rod bearings as fast as those heavy cast iron pistons do! We did that for a lot of years with no problems with the overbore. It will cost less than half what a 6-sleeve job does.
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!