When the car sits a day or more - first starting up pretty loud ticking but subsides once oil starts flowing - sound you get when changing oil. Again with the scope - nothing on the valve covers, engine pan, can hear it good when scoping the headers. I tried the power braking and it did not get louder. More pronounced at idle. I'm going to tighten headers up this weekend - just put them on a couple of weeks ago and did not retighten afterwards. I put these bolt clips (stage 8?) that are suppose to eep the bolts from loosening up. Had the ticking before putting header on which led me to beleive it's something else.

 

Put the car in gear, stand on the brake, and slowly push on the accelerator pedal = definition of power braking.

Be careful; don't do this in front of a cinder-block wall or a big tree.

 

Load engine by power braking and observe noise.
Pat

What do you mean by "power braking"?

 

Load engine by power braking and observe noise. If exhaust leak, it should get louder; if not, then consider valvetrain/piston slap, etc..

Pat

 

It does get worse as it gets hotter. Was only doing on one side - now on both - I'll tighten up header this weekend and see if it helps.

What about lifters - would it have the same symptom?

 

Sounds like an exhaust leak at the manifolds. A VERY general rule is that a valve tap will get better as the engine gets hotter, and an exhaust leak gets worse as the engine gets hotter.

Put your hand as close to the manifold as you can and see if you can feel the leak. Sometimes it's difficult, though, to discern the air from an exhaust leak from that of the fan.