I love the 4mil for a step up in all around power. A good mid to upper end port job to match. A set of shearer in frame pipes and timing plate on +6. Around 175 to 180 PSI on a NOSS cool head setup with custom domes. This will bring it to the 80 hp range at the wheels with the right port job. If you cant have fun with that then I don't know what to tell you. :biggrin: