Stroker Motor wont Rev pass 5200Rpm

9-10 pounds of boost requires a pretty good ignition system. And plugs gapped down a little. Hopefully you’ve got both of those two things. My second thought is I hope it’s not detonating at 52-5300 because that will stop it from making power and accelerating and also destroy it. Last thought is it’s floating the valves. You should figure out what camshaft is in it and make sure the springs are adequate. Pull a plug and send us a pic. Close up and clear.