What's acceptable leak down per cylinder on 23 degree 406 sbc 12.5:1 compression. Going thru some oil and breathers not covered. Checked all 8 and ranged from 10% lowest to 28% highest on couple cylinders. Normal was 15 to 18 majority cylinders. Wet sump on alky if really matters with 2 barrel. Could it be rings or valve guides or?? Thanks for info and assistance