Big blocks have always been notorious for pumping all the oil up top. Bigger oil pan, windage tray are necessities at higher RPMs. But, they won't help much if the return is restricted. Check for casting slag in the oil return holes in the heads. This is always a problem if they are OE heads. (the triangle shaped holes in lower corner)  

I have a '66 corvette 327/300 in my 1969 Camaro. Recently a  mechanic replaced the oil filter adapter due to a broken bypass spring? after 3 failed attempts with the new adapter this guy claimed that he was successful... not the case. I tried another style adapter, but still cannot completely stop the oil from dripping.
Any suggestions? the latest adapter doesn't appear to have a bypass function and I didn't buy either one so I don't know the brands used. Im open to suggestions if anyone knows a specific brand they've used or troubleshooting technique.  

I have never seen an engine that would have the same oil pressure at idle hot/cold. 59 lbs. is way overkill at idle. GM and most knowlegable builders know that 10 lbs. per 1000rpm is more than adequate. If clearances are opened up exessivly wide then you may need a high volume pump as a band-aid. Other than that its just robbing horsepower and creating heat. I have to admit, it took me a while to realize that. Having been in every nook and cranny of many Big Chevy engines and being involved with modifying oil pumps, the most successful has been a standard volume pump, machined with pressure balance grooves, stock-style pick-up 3/8 clearance to pan and .0025 cover-gear clearance. If pressure is on the low side, go with a heavier spring. Your high RPM drop sounds like cavitation, which as you know is bad news for bearings. Usualy the pick-up is to blame for aerating the oil. You did not mention if you changed styles when you changed pump. Also, have you tried a different pressure gauge? Like I said before, I have never seen an engine have as much oil pressure hot/cold. Good luck.  

Hi sertn7142, your issue sounds like there isnt a bypass in the adapter and oil is pushing out of the O-ring. I do not use the adapter with the bypass, because so much oil goes unfiltered. But I always use a high quality filter with a high burst strength. And you must allow it to warm thoroughly before any kind of RPM's. Also not to heavy on the oil weight. Hope this helps.  

That is great advice.  

Thank you very much for your response... time will tell!