Hey, well I think I found what I'm going to buy for my car at the moment. Hedman shoryy headers and a hooker aerochamber muffler. Could I get 25 more hp out of this with my 81 305 from a chevy van with 10,000 miles on it. If not I hope I can atleast get 20. Will this make my car sound alot better? The reason i'm not getting the 3in. catback is I dont plan on putting anymore money into this car and I would think the stock pipe would give suffcient flow for the stock 305. Let me know and thanks.