pressurising the sump

what I have is A460 block, 4.625 pistons, low compression rings, gapless top rings, 4 stage dry sump set up, 3 scavenge 1 pressure dash 12
hat injected on metho, done leak down test and all is fine, done compression test all read within 5 pound 250.
just seems to be building pressure,
any suggestions

That engine def needs a 4 stage vacumn pump for sure.