I recently got my head gasket fixed and exhaust, intake manifold, and headers installed. Car is running again for about 6 days now, and Im hearing what I think may be a problem. When I accelerate, im hearing a high pitched whistling sound. It makes me think a belt is on wrong or something, but it is super loud. I can hear this when outside of the car as well as inside. Just kind of wondering where you guys think I should start looking first.

My throttle body did that right after I installed it. I had a small air leak there that caused a pretty nasty whistle.

If you're using a Jeep TB it'll do that all the time.

I actually havent replaced the throttle body yet. I drove it some more and now it does it sporadically when idling or accelerating. Im thinking a belt could be loose/tight or something along those lines. Could power steering pump be doing this?

Might be the timing belt on slightly too tight. Sometimes if you put them on pretty tight, the gears will whine/whistle under rpm increase. Mine do it and after a week and about 175 miles, it is starting to decrease. I can hear it inside as well as outside my car (even over my loud-ass exhaust) but it is starting to dwindle. I don't foresee any problems with it being tight as long as it isn't TOO terribly tight to the point it shreds, but I don't know. If it is too tight, it will slowly stretch as you drive it more, after all it is rubber. Could also be your power steering belt tight or moisture/liquid on one or more belts. It's kinda hard to tell, but it definately sounds belt-related.

Aha! Just the answer I was looking for. I think it may be a few of those problems. My timing belt was on good and tight, possibly too tight. I did get some power steering fluid on the timing belt, and the powersteering pump belt was questionable as well. Thank you. this gives me enough info to go fix it. Much appreciated!