So I have been noticing kind of like a knock at idle only. Kind of a diesel engine noise. Now today while driving on my way to the store, on light acceleration I could hear a tapping. The tapping seems to me to be as fast as the rockers "sowing machine" noise and sounds kind of like, I don't know, metal on metal high pitch tap noise?

 

Could be something in the valvetrain, but the first thing I'd check is my exhaust manifold bolts/gaskets. A leak at the head sounds like a hard tap-tap-tap that varies with engine speed. You'll especially hear it under tunnels and close overpasses.

 

Ha i can vouche for that definately check your exhast gaskets i had one go bad and i could have sworn it was valvtrain issues.

 

How can I check them without taking the manifolds off? And I've got the copper ones on there, do they need periodic retorquing or even like a retorque after a break in period?

 

I had copper gaskets on my last set of headers and they were AWFUL. I blew them both out and could not get them to seal no matter how I torqued them.

 

Hmm, well I'm about to get a 306 put in within a couple weeks, so I guess I could get him to take headers off to check gaskets.

 

You should periodically check your bolts if you didn't put threadlocker on the manifold bolts. I have heard that the copper gaskets suck look into a set of felpro gaskets they are relatively cheap and will last and seal better than most every other gasket out there.

 

He had some other metal ones that didn't seal all the way so he put copper and they sealed a lot better. Are there any stores that sell FelPro gaskets?

 

Put your car in a high gear and step on the gas. If the tapping becomes louder then it is an exhaust leak. You may also be able to check around the spark plug boots and plugs themselves for any kind of exhaust/carbon/black buildup...