Offset grind the 270/302 crankshaft to 4 1/4" stroke length by using a 2.100" Chevy 350 V8 rod bearing. Sleeve a 7.1" H-beam Chevy big block V8 rod down to use the small block bearing. Use the big block rod bearing pinned or held in place with brass flat head machine screws as a reducer sleeve, honed to fit the OD of the 350 rod bearing. Use a MOPAR 360 piston .020" oversize and hone the flanged Diesel sleeves out about .005" to match the piston size. Use a bronze bushing in the connecting rod small end to match the MOPAR wrist pin size. Teflon or aluminum buttons in the ends of the wrist pins to keep them centered. All of the above modifications assume the machinist has FAR above average skills. Major engine modifications involving parts from other manufacturers' engines are not a game for armchair quarterbacks.

I grew up in the 1950s watching my father do "impossible" modifications on flathead Ford engines, and I've been doing similar stuff for 50+ years, so I'm definitely not smoking wacky tabaccy!

It would probably also be possible to build a 301 cubic inch / 4 1/4" stroke GMC 270 using standard bore 292 Chevy 6 cylinder pistons. (No sleeves- - - -.090" oversize) 270s are a lot more plentiful (and less expensive) than 302s!
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
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