Squeaky/tapping noise on #8 cylinder

[Mrturner1]

Hey guys, I'll give you a quick run down of what it is, and what's goin on. I'm gonna pull the valve cover after I post this and take a look.

It's a 1970 c10. Just did a top end on it, it's been an on going tuning lesson for me, and I think whatever is happening is part of the problem. New heads, cam and lifters, intake manifold. I went with a Comp 280H magnum cam. I used 1.5 roller tip rocker arms. I've been trying different timing settings to see what it likes, right now I'm at 34*. It's got 12* initial, and it has a GM performance HEI (not sure if the vacuum advance is adjustable on those)

Drove it to town and it was running good, not great. Noticed a little knocking type noise at #8 this more but nothing loud. After I left the store, it was hard to start, had to hold the gas pedal to the floor. Idled funky and real low rpm so I brapped the throttle a few times to get it to idle. It went back to normal idle. Found a strait away coming home and accelerated hard but never letting it kick down, held 3rd gear, and it started studdering at about 3300rpm so I let off. Drove home ok, but it didn't like that hard acceleration at all. Stopped at the mail box and heard that same cylinder but now it was making a squeaking kindof noise with a tap. Definetly not an exhaust leak, and definetly the same cylinder I heard earlier when it was just a slight tap.

What do you guys think? Keep in mind it was my very first top end, and I did it myself including the valve adjusting and setting preload. I'm gonna go pull the valve cover, thanks for any input guys