First things first i have a 1990 SC auto with OD this is my first. I would like to know some small things i can do to bump up some hp. where can i start looking for parts that are credible. I have already done some research but would like some input on where to start.
First thing to do is save money. That car is old and some repairs can be expensive (i.e. brake system, brakes, suspension). Thus make sure you budget something each month for just general upkeep of the car.
Second, become a member of the site. I know it a mess right now trying to join, but there are some great threads in the members area that discuss basic bolt ons, including this one which documents HP gains with each change.
http://www.sccoa.com/forums/showthread.php?t=98215&highlight=air+silencer
Third, save up for a Quarterhorse and wide band sensor. Most of the changes you do to your car help reliability, but performance increase is hindered due to the stock tune of the car. You'll gain benefit without it, but with it your benefit is maximized.
Fourth, if it has stock exhaust, consider replacing it. When replacing it consider your horsepower goals before selecting the replacement. You don't want to go with pipes too big. The size of the stock exhaust isn't the main problem, it's the configuration with necked down areas, and sharp 90 degree bends.
Fifth, intake side. If you do anything to spin the blower faster, you should get a larger throttle body. The stock unit is restrictive. If it has the stock air silencer, you can remove that, and with the addition of a K&N panel filter you'll sound like you have gained significant HP, if not actually gaining significant HP.
I have a 1990 SC AOD with a 5% overdrive on the blower, custom exhaust, lentech valve body, and K&N Panel filter and over 150k miles(and new head gaskets). Otherwise the car is essentially stock. Best time down the 1/4 mile track with DOT drag tires: 14.663@91.62mph with a 60' at 2.075.