yeah just like the last post it is hard to determine the gains, and pinpointing where the power is coming from is hard, buy running headers and dual exhaust, you are supplementing the exhaust flow making it exhale better and more efficient, and same with your intake swap more air in, and a better mixture. to really feel a punch you need to put in a better camshaft. the heads matched to a decent cam and a decent intake is where you will feel the power. there are many options to run, if you choose to change a cam keep it fairly resonable in lift, not sure what heads you run but if they are iron and not vortecs stay under .480" lift that way the stock springs can be used. you are on the right track and if a tight budget is in play hyd. cams are cheap, so it will be easy on the pocket book.....good luck and hope this helps