Hello all. Quick recap:
Recently put in a '74 B20F with 30k on it, K-cam, aluminum timing gears, D jet intake and injection components (was originally K jet), controlled by megasquirt getting a tach signal from the negative coil terminal.

Put the engine in, started it up and it sounded horrible. Checked valve lash to find PO had set valves to about .04 and I tightened them down to .020 warm. He said he made them so loose to get more vacuum. So a lot of the noise went away and I wasn't as worried that I bought a bum motor. So after chasing down a few other gremlins the thing idles really nice, but when the rpms go over a certain range (probably 1-2k) there is a horrible clacking metallic sound from the distributor area.

When I bought the engine I was told that the distributor was making noise because it was on it's way out (1975 breakerless 240 ignition). So when I put the engine in I put in my old trusty cast iron mechanical advance unit. But it made a heck of a racket. I disassembled it to find that the pivot points on the weights were way out of round and I figured that was what was making the noise (one weight could contact the body of the distributor). So I put in the POs 1975 distributor after putting in another shim to get rid of some extra axial play (and installing the black box) and the thing still makes the noise. I pulled the distributor drive gear out and it looked a little worn but not "metal clanking sound" worn, and the gear on the camshaft looked OK as much as I could see of it.

I have tried three distributors and they all make the noise. I was so weary of banging advance weights that I even cobbled and welded an old breakerless distributor to lock out the centrifugal action. The sound seems to be coming from the distributor, or the base of the distributors (using a stethescope). But it is loudest when the stethescope is placed on the distributor body or the distributor clamp.

The noise seemed to be a little different with each distributor I put in. With some distributors it would make the racket a soon as I revved above 1.5k rpm, but with the one I locked out the centrifugal device (vacuum device still operating) it seemed to make the sound at higher rpms and when over running the engine (in gear downhill). I didn't dial in the timing of each distributor as I tried it so now I am wondering if the noise could be serious pinging (I can't say that I know exactly what pinging sounds like since all of my old motors didn't have enough compression). Any ideas would be greatly appreciated I don't no what to check next. What could be making such noise??

Thanks in advance,

Mario m.