What's the oil pressure? If it's getting low when the engine heats up, that's why the lifters are bleeding down. Where did you get the idea a high volume pump will cause seals to leak? None of the crankshaft seals have oil pressure applied to them, so there's no way more pressure or volume will cause leakage.
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!