So my buddy has this 1999 Z28 LS1 M6 w/ 70,xxx miles. Mods are Lid, filter, some LS1 free mods, & a CatBack Exhaust.

Anyway, so we went to do a quick run between my 3rd gen and him in his 4th gen. Of course he beat me, but I think he over-rev'd a gear or missed a shift.

So the car started to make a "ticking" from under the hood that goes faster as rpms go up. And it kinda feels like it stops pulling around 5500rpms now. What could be the cause of this tick?

 

Bent pushrods likely, especially since there was an over-rev. I got 2 sets if someone needs to buy them for cheap.

 

+1 for a bent pushrod.
Tell him to pull the valve cover and check. its an hour job to pull the covers, pull the rockers, check the pushrobs, and put everything back together.

 

yup pull em out and roll em on a flat surface check for staightness if not straight then well its time for some new ones

 

I just did that very same thing but my car is fine, I am saying extra prayers tonight. I hope your friend ahs only bent his pushrods. I am going to do mine soon anyway (I went from 3rd to 2nd at 6k, and the car screamed, so how much is that in 2nd

 

ouch, ive done that before, but not anywhere near 6k, id say my miship happened around 4500 and i still consider myself lucky.

 

Yep, your buddy needs new pushrods.

 

+1 to pushrod