Pretty sure it's the compression release??
 

I have been noticing a noise for a while and have bneen chasing it. Sounds kind of like a chirp or whistling sound. At first I thought maybe an exhaust leak but no I'm pretty sure it's coming from a compression release. It's most noticable in 3rd gear around 1800 rpm when I roll on it. Anybody got any ideas?

Take them out and clean them, they sometimes get a piece of carbon in them and won't seal all the way. The best way to find out if they are the cause

A chirp a start up is normally a base gasket leak.....any oil around the bottom of the cylinders?

No oil...it's clean as can be.
It doesn't do it at start up (if that's what you mean?). I notice it initially on moderate to hard acceleration when going from around 2000 rpm. If I hit it at a higher rpm it isn't noticable. At least I can't hear it?

Another thing I have noticed is a small hesitation or flat spot when bliping the throttle. Most often notice this when coming to a stop and the starting again. With the 10:5-1 compresiion I give a little throttle to keep it form stallling out...plus it just sounds good. ;) If the compression release is sticking would this or could this be a symptom?

Sprinkle some baby powder on the belt drive side and see if it goes away for awhile.

I'll bite...What's that going to tell me?

Talcum acts like a lubricant. It will only last a short while. Just isolating that its not belt noise. Try it some day on an older car with older drive belts making a lot of noise. It will quite right down if its just the belts and not a bearing like the alternator or water pump. My drive belt makes a raspy snappy sound at a certain speed in 3rd gear

CR's whistling
 

What did you ever find out about this issue. Mine now does this, though at a bit higher rpm, but it is always when accelerating under load. Nothing at idle or when cruising at a static speed & rpm. Didn't seem to happen until I had the manual CR's installed. They sometimes stick at start-up, but a blip of the throttle usually closes them up.

Thanks!

I am not an ace mechanic but if it is leaking compression I don't think it would run well at all, if any! I can't think of the name of it but they sell leak detection spray, it will bubble if there is a leak but then if there is a leak I wouldn't want to spray anything on there and have it leak down into the heads. Just my $0.02 for what it's worth.