Blown alky cranking pressure

Just checked our 540 KB/Olds. It made about 60 psi. Leaked less than 10%. Checked the degree on the cam,it was fine. We have run the same cam/11.5-1 compression before and it made 90-100 psi. I'm wondering if it's starter rpm..we changed to a CSR gear starter. It's an Oddy setup if that matters. What kind of numbers do you guys normally see?