350 horsepower tips

[mrbee]

i made this post a few days ago and i want to give some of those experts out there a little more knowledege about my engine. Its a 74-75 model 350 engine in a 81 buick regal. looking to get more power out of it. Seems like it has a sort of slow take off. it has headers 1.5 comp roller rockers, edel 650 carb, air gap intake, 292 comp cam, 9 to 1 compression ratio, hooked up to a 350 tranny with 2800 stall. hadnt did anything to the rear end yet but im told this will help alot. It has regular gm heads 72cc. going to change the heads in a couple months. What is the best exhaust to put on it ?it has dual right now but they aren't flowmaster or any thing looking for a better deeper sound. it has cats on the duals right now i was told to cut them off because its to restricted for that and i have a way of getting around the emission test. please give me some help guys!!! i have $2000 in the engine right now and i dont look to spend no more than maybe another grand.Should i use the x pipe exhaust? What exactly does the MSD ignition box do and should i get one?