Tap,tap,tap,...........Tap,tap,tap,............Tap ,tap,tap,............Tap,tap,tap,............

At about 1700 rpm it is the most noticeable. Three taps, at the same speed you would knock on a door, then a pause for the same amount of time. I got up on top of the engine, and it seems to be centered in the engine, deep.
At 1900 rpm there might be four taps, at 1200 two.
I've always had a very noisy valve train, I never adjusted it since new, and now I won't be able to do anything until it gets warm outside. The cadence of this new noise is just plain weird.
Comp Hyd 222 224 .566 .568 115 LSA, Comp 875 roller lifters, Comp 3153 timing chain set, Comp 13753 roller rockers, Comp 3/8" x 7.500" pushrods.

 

probably those long pushrods.

 

Elaborate

 

well stock size is 7.4, which is what most people use. i've heard of a few people with huge cams running 7.425 but with your small cam you should just be using stock size pushrods.

 

Did you check valvetrain geometry when you put it together? Hell even on my 331 ford with dart heads the rods are only .020 longer then stock.

 

I paid to have it built.

 

Those pushrods are extremely long.... .100" longer than stock may want to change them out to 7.4's or 7.425's

 

Might they be longer because I have AFR heads?

 

Put up a vid for us. My guess is either bent pushrod, broken spring, broken rocker or exhaust rattle on the frame at a certain engine harmonic

 

I tried taking a video several times, it is too dificult to distinguish the noise. I even videoed inside while I was driving, then all you can hear is exhaust noise and tire tread noise. My tires are as quiet as any car's, and my exhaust is stock. It's weird how cameras decide how to equalize the sound. The noise is so obvious to my (nearly) human ears.
It sounds like somebody tapping on the inside of the aluminum intake manifold with a 10mm wrench, in the cadence I described in the first post.