Before we discuss anything let's start with budget...
Being a college kid you're probably on the cheap bigly (as our new President would say) so removing weight would be the cheapest. That said you're in college so you might actually want to take a girl on a date so don't go too nuts. They're not really into bare-bones cars that smell like gas and run like crap so first things first: sort it out so it runs well and doesn't leave you smelling like a used oil drum.
Then onto the fun stuff: Gearing: Not sure which rear you have. 10 bolts: 8.2? 8.5? Either one will be fine for the car to start with. Do you know the gearing?
I'm looking at gear changes in my 8.2. Right now they're extremely tall. Combined with my powerglide means 60 mph in 1st gear. Sure she moves pretty good to get there but still...
So rear end would be cheapest. If you just swap gears yourself you're looking at $200 in parts and tools. If you plan to add posi: $600 all-in for a kit (assuming 8.2).
Next would be the head situation. We have to fix your head. It's all wrong! Wrong I tell you!
You have an integrated head. Meaning you can't put the fun stuff on it. You can't swap in a 4bbl or aftermarket headers.
So get a head. You can probably find one with the stock manifolds too. Should be easy enough to change out to start and won't add any hp but will make it so you can add it later. I'm sure someone around here has one laying around or you can go on Craigslist or just ask around locally. A lot of people have pulled these engines and have them sitting out back. You might even score it for free!
Then once you get your head straight move on to exhaust headers. That made a HUGE difference for me and was the start of my addiction.
I went with Langdon headers and a single 2.5" exhaust. Runs well and sounds great! Added quite a bit of punch too! Figure about $700-800 all in once you add in new exhaust. Get someone who knows what they're doing or it'll cost you another $300 to fix it later. Ask how I know...
Now you're onto the intake side. Offy intakes are cheapest and have great streetability. You'll want to heat it, though.
a 390 CFM carb or FiTech EFI would sit on top. I got my 390 used and had to rebuild it. Good learning experience, sure, but I plan on going EFI and would have skipped the carb had it not been $2,000+ plus when I did mine. Now Holley Sniper and FiTech are both around $1,000 for the setup. Expensive on a college budget but it'll eliminate the gas smell and give you better MPG's so...
You can also do a cam. I went too mild on mine. Wishing I had gone more aggressive but I digress...
Another cheap way to free up 15 hp is to ditch the mechanical cooling fan and go electric. I did an electric pusher fan and the car is much quieter, cooling is fine and I have free hp. All in you're around $120 there. I bought a cheap replacement fan from Autozone, a relay, and push-through temp sensor (the type that you push between the vanes on your radiator) and it works well.
You didn't say what trans you have.
Now want to get serious? Start with the head again. This time lump ports and oversized valves. Probably about $800 to have a machine shop do it.
Next pistons: get flatties and you just upped your compression.
Really want to get serious? SPI makes a turbo exhaust manifold. Now you're talkin!
I know this will be sacriledge to say here but it's a fortune to build a 6. It's satisfying as all heck, to be sure, but if you really want to go cheap get a junkyard 350 and rebuild it yourself. It'll be the same or more HP than everything I mentioned above (except maybe turbo) and be about $5,000 less in costs.
Don't discount the 6 though. She's a neat little engine that can surprise people.
Here's mine:
http://i.imgur.com/MRxtWKE.jpg?1See? No spaghetti!
