Oil filter bypass

[vette427-sbc]

My oil pressure has been dropping under load recently. I was told that the oil filter bypass might be stuck, and it would be better to just block it off anyway. Any tutorials on how to do this? A quick google search yielded nothing.
Some background on the oiling system...
I still have the stock corvette baffled oil pan, had the stock pump, recently replaced with a high volume, high pressure Melling pump. (same pressure drops with both pumps, so I dont think it is starving at the pickup). Pressure is 25lbs at idle and peaks to 70+lbs at 5000 RPM before dropping to 25lbs again. Valvoline 10/40 conventional with a WIX filter. Any other ideas as to what it might be besides the bypass? Pressure does not drop under hard braking/cornering either.

-Chris