iv been using morels for about 10yrs now under 600#open pressure. no failures yet. had them rebuilt 3yrs ago. i think i paid $250 for them at the time. sounds like the sheens or morel are the way to go. the morels work great in an unbushed block. the lifter oil galleys leaked real bad on my 360 block with comp and crane lifters. im now going to use them under 650# on my current combo. we will see how it go's.