Grooving lifter bores

Actually, the Crower Cam Saver lifters I recommended have grooves in the sides that do the same as what the lifter bore tool does. It still supplies pressurized oil to the lifters. I spoke with Crower directly and they said there is no change in oil pressure. I also know someone locally who runs them and he has no oil pressure problems.

I don't see a problem with grooving the bores or using the Crower lifters. If either cause problems, the tool nor the lifters would not sell. And quite obviously, they do.