Yes, roller rockers would definetly free up so horsepower. they say you can expect anywhere from 15 to 30 horsepower increase, your valve train will thank you in the long run.
I've seen allot of good deals on here for them, check in the engine parts section under drag race. They are many venders that would love to help you out.
Also I say this allot only because its the has the most bang for your buck. nitrous is a quick & easy and safe upgrade that's afforable and its harmless if used in small quanties on stock motors. You can get a small adjustable kit for about 300 bucks and put the 75 hp jets in it and have a blast and the best thing is it will not affect you emissions at all.
Goodluck Charles