I think one .060 washer will raise the bypass pressure up to over 100 Lbs. at idle cold on a high volume pump with the high pressure black spring
It has been a long, long time since I tried adding pressure to those pumps, I usually cut one to two coils off the black springs to get 10 Lbs. per 1000 RPM with hot oil over 160 F
I think Mellings and Speed Pro are now, for the last two or two and half years, installing standard pressure springs in there high volume pumps instead of the high pressure springs, maybe not