Lots of good advice. I'll add it's well known there's a lot of junk pumps on the market last few years. I always blueprint the original or build my own. If you've got a non orig pump the bypass provision may be poor.I've seen oil pickup screens too close to sump bottom. May not be your problem but something to consider. Been professional 65 yrs and remember the 50-53 235 low pressure hydraulic lifter engs idled at 3 lbs.hot oil perfectly OK. Let it idle for a while and she'd start ticking. Lifter bores couldn't have much more than '001" or it'd be a common trait. Many hydr lifter engs I do like '30s V12 Packards and V16 Caddys, etc run 5lbs idle. That's factory spec. Pumps are linear also usually too big in the first place. A lot of people use the rule of thumb on full pressure engs of 10 lbs per 1000 RPM. Not a bad place to start for most engs here. JME David
