I'll be pulling my motor this fall to remove "Y" pipe to get rid of silent choice exhaust. I will also be painting motor as well as repainting bilge and doing some re-rigging. What I am wondering if while the motor is out, what kind of performance gains would I get out of adding the right combination of roller cam, roller lifters and rockers. Intake manifold and carb. Motor is a 1990 454 Magnum 365hp with Imco Thumper Power Exhaust. Estimated to be 385hp with exhaust. Motor only has 100hrs. on it since it was freshened.