The Buick 215 pistons would require a longer rod to reach the top of the block, such as a GMC six (248, 270, etc). 85 HP flathead Ford V8 rods are also the same length, and a LOT lighter weight. The GMC rod runs the same size crankshaft journal OD as a Chevy stovebolt, but it's about 1/4" wider at the big end. It's 7" long. Milling the GMC big end width down to match the Chevy journal width gives a builder a better choice of pistons to use because of the longer rod length. BTW- - - - -I just bought (stole) a set of used 270 GMC rods and domed pistons from an Ebay seller who had no idea of their value, and I won't have a use for the pistons for any of my projects. They're available for horsetrades!
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!