[Keithc8]

The 428 CJ blocks did not have a restrictor the from the factory. The person that built the engine last may have installed restrictors in the cross over passages. Other than that you should be able install a new hydraulic flat tappet camshaft and lifters. You may want to check the spring pressures and shoot for about 120 on the seat and about 300 open. I have some nice grinds that we use in our restoration engines that work well. Remember all of the break in procedures for the new camshaft.

Thanks, Keith Craft