[ThreeNuts]

Originally Posted by SRGN

If there was witness marks on the upper shell of the rod bearings, that would be detonation. Upper part of the cam bearings is more likely an oiling issue or a bent cam. If you want to work on the tune, I have a wideband and a lot of diagnostic equipment. You are welcome to drive up to my little shop and I'll help figure it out. I'm usually up there when I'm not at my regular job.

Thank you! Be careful what you offer; I just might!

I have all of the bearing shells (I always insist on retaining all of the old parts) - I'll check the rod bottom ends...not sure which one is the top one - I guess if they're scrubbed, I'll know...

I did order a new accelerator piston. The issue is not noticeable in Park.

The vacuum was right around 19hg, with a 1"-hg steady flutter, which I keep forgetting is normal for carbureted cars.

I may put the tach & vacuum meters in the car (with really long extensions) and drive it around to rule in/out it being ignition or fuel. It's running the Pertronix system I installed in 2001; I did replace the cap, rotor, plugs & wires along with the coil with this rebuild.

I'll push the timing up & see if the clatter goes away.