So I'm Looking for 500whp
 

I'm going to be upgrading again with a healthy sized cam along with some nitrous and I am looking to be at around 500whp. At that power level, what is prone to go wrong with these BESIDES the engine internals. I'm talking about axles, splines, tranny, rear, suspension? Any feedback is appreciated.

At that power level I would say tranny, clutch, output shaft more than likely. The rest is hit or miss.

I havent had any problems, but i've only been to the track twice since putting the engine in, and I dont launch hard.

Highway rolling? stock driveline
street/strip? basic driveline mods
serious drag? built rear and brace and adjustable shocks

clutch will be shot soon for sure. everything else is just when the time comes. could be your first launch, or your 3000th

Based on my experience, once you start drag racing things will break in the following order:
1) Clutch
2) Output shaft
3) Trans

After that it can be any of the following: rear end, engine(probably pistons or rods), torque tube bushings.

You get the idea. So you can either just wait until they break and fix them then or replace everything now. How much money do you have?

I had a bad run of luck last year and had to replace the following:
forged engine, trans, rear end, rebuilt torque tube

If you aren't a serious drag racer, the only thing I would worry about is the clutch. If you are serious about dragging, then you know what you will need to upgrade.