I have tried to squeeze all the bolt on horsepower I can out of the 1995 Chevy 350 cid engine in my truck. I have an Airaid cold air intake, JBA headers, a high-flow cat, and flowmaster series 40 cat back exhaust. I still feel like the truck is sluggish. What else should/can I do? Do I need an ignition system, or maybe a whole new intake manifold? How many horses should I be getting at the rear wheels with what I have already done?