The Melling M-45 pump fits later model 235s and 261s from 1955-63 or so. The M-29 fits 216s and 235's without the offset in the passenger's side oil pan rail. Both of them have more than enough volume to keep any healthy engine lubricated. In 65+ years of building engines, I've never seen a non-racing engine that can benefit from a "high volume" oil pump. If the oil pressure is low for some reason, find the worn out bearings and replace them. All that pumping outrageous amounts of oil does is wastes horsepower that could be used to drive the vehicle, and overstress parts like distributor and camshaft gears and shears off pump drives. High oil volume and/or pressure is a solution in search of a problem.
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!