The L98 engine is a tuned port injection 5.7L 350 cubic inch engine.
Some common modifications like any other engine are going to be improving air flow....
One of the first places to start is to get the exaust flowing better. Headers, high flow converter and cat-back exaust systems are great for street cars. Even better flowing or bigger headers are avaiable for race versions. True dual pipes with high flow "race" type mufflers.
The next area is the intake, on the camaros with the dual filter air box things like taking out the water baffles or even cutting out the bottom of the box to get better are a good start. Next would be to get a good flowing filter such as a gauze type like a K&N. Throttle body air foils are a very common mods for some people using the stock throttle body. After market throttle bodies are also available with increased sizes from mild to wild....52,58 MM in the stock style and for more radical combos monoblade throttle bodies that can flow alot of air.
Intake porting or aftermarket intake runners will increase air flow also. The long runners of the L98 make it a little less desireable for high RPM power so many people have adapted other type of intake systems. Some resemble a carburated style intake with a large 4 barrel throttle body. Things like mini rams (similar to an LT1) or othe fuel injected intakes have also been used with great results. Holley has also released a "steath ram" intake that claims serious h.p. gains even on a stock engine.
Roller rockers,camshafts and the correct "cam package" are worth alot of money....though they will require quite a bit of work to perform. After installing a new camshaft most times a new computer chip will need to be installed. The camshaft rockers springs and assosiated parts need to compliment each other. So shop wisely and do your homework. This engine uses a factory hydrolic roller type lifter.
Cylinder heads....Well the real power is in the heads, your standard small block chevrolet info applies here for the most part. Without getting into alot of detail about heads the main points are to get something that will flow good with a small runner for a streetable application. There are alot of good books avaialable on cylinder heads. I would suggest investing in a few.
Stroker kits....these kits are the "bottom end" of the engine...and stroker refers to increasing the stroke of the crankshaft. the stock stroke being a 3.48 can be "stroked" or increased to a 3.75" and with a small overbore and new pistons would result in increasing the cubic inch or displacement of the engine from a 350 to a 383. Basically think of the bottom end as an air pump....a stroker kit wil make your air pump bigger. This wil mean better heads, bigger cam and all the other parts will need to compliment it to get the best results.
Aftermarket tuning or engine management such as DFI from accel or F.A.S.T are great for tuning high powered combos in real time. this eliminates the needs for chips etc.