i take it you have the correct size shells,it doesent have oversized housings [mainbrgs] [cambrgs] or cam follower sleeves, and have you checked your relief valve,....does it have an external oil cooler ,these can block up too .....i have seen all of these problems on a cvh , also check the pickup pipe and make sure where it bolts to the pump that it is`nt warped, i also seem to recall that their is a relief valve in the head somewhere check that too ...............blaazer2