I was told by Lunati not to exceed 430# on the stock GM dogbone lifters. I have turned them to 7000rpm at just over 400# open pressure.

Joe, How many hours do you run the springs/lifters before changing.

Well Gary, I don't believe I ever had a boat long enough to find their failure point. Typically I would have a boat 4-5 years and put 50-70 hrs per year on them. Camshafts would be in the .630 lift range. I would think that 300hrs would be a good point to check them.

We're running 170lbs on the seat with 430lbs on stock 525 cams. Using johnson lifters. No issues.