Let me throw some ideas your way. First off you can increase power by induction, exhaust, or going to larger cubic inches. Let's start with induction. Easy one here, get a low restriction air filter like K&N. If it's a barrel carb on your engine, swap out the jets for larger ones or go to a 4 barrel. Add a little timing to the engine but watch out for pinging, run a little higher octane Buy good plugs and gap them correctly, then index them. SOme say it does add power, some say not. Get belts that just run the necessities like: water pump, alternator and not the a/c compressor or the P/S pump. Get a lower temp thermostat than stock calls for A 78 350 should have HEI, make sure it does. If not, upgrade to it. Buy an aftermarket intake that matches up with your carb Install a better cam more lift duration Or you could buy a nitros kit, install it and if you engine is in good shape and you don't get crazy with the power adding. There are plenty more but I'm not sure what your budget is. Get a SUmmit or Jegs catalogue and look up the prices of these suggestions for an idea what they cost. I basically posted the cheap ones I know Exhaust: Go from single exhaust to duals and go larger say from 2.25 to 2.50 and install an X pipe Get low restriction mufflers Check your O2 sensors to make sure they are working properly and upgrade to better if available Install headers Powder coat your headers or use header wrap. Get hi flow catalytic converters You can port match your heads if you know what you are doing Buy thinner head gaskets to increase compression There's some starters for you. Good luck and when you're budget gets bigger you can do bore, and stroke and turbos and blowers. The more horsepower you want, the more it costs. Oh above all else , keep the engine tuned as you make upgrades. Don't just throw parts on and believe they are working. Keep a good Air to fuel ratio as you go. Tune tune tune If it doesn't have a tuned (header extration system) exhaust, that's a good first start. Also, a low backpressure exhaust can help as well. Beyond that, you won't get much improvement until you get into the engine. High compression pistons can make a difference, especially if you live in a higher elevation, such as Denver or most of Wyoming, Utah or Montana. Unfortunately, if you get high compression pistons you'll need higher octane fuel. To avoid the necessity of aviation fuel, don't go more than 1 point above original manufacturers pistons. Also, if you're pulling the engine apart, you can get some extra HP from a modified camshaft. If you live in a state that requires emission inspections you'll need to make sure you don't go too radical on the camshaft, perhaps an RV cam would be about as far as you'd dare. Beyond those, more HP will require significant changes. HP is about combustion forces; to increase combustion forces you either need more fuel/air in, more exhaust gas out or higher efficiency of the combustion. An improved ignition system or components can help, but generally you don't get that much increase in HP, especially if it's already burning "clean". Quite a few of the aftermarket accessories that claim to increase HP are just a way of making the marketers more money. There are quite a few products that are real junk. Remember that GM (in this case) wants to give you the most HP without going over the Federal emissions standards, so they've already done quite a bit. You might be able to squeeze a little out by putting less emphasis on emissions, but generally GM has already put their engineers on the issues.