Weird engine trouble

[tortuga]

Originally Posted by sunman

Big hydro cam
I’d check under valve cover
Maybe lifter makes noise only when cylinder pressure is up
Do the easy stuff first

Originally thought lifter or exh leak, pulling the plug wire and stopping the noise initially was a relief, but when i couldn’t cure it with swapping plugs/wires i started worrying. Swapped boxes, distributors, pulled the valve cover, ran it (big oily mess)…. I am seeing arcing at the plug, but even sliding a hose over the boot did nothing…

[Gaz64]

Originally Posted by tortuga

Originally thought lifter or exh leak, pulling the plug wire and stopping the noise initially was a relief, but when i couldn’t cure it with swapping plugs/wires i started worrying. Swapped boxes, distributors, pulled the valve cover, ran it (big oily mess)…. I am seeing arcing at the plug, but even sliding a hose over the boot did nothing…

Can we elaborate more on this?
You said you changed the plug AND the lead, and this still happens?
Is the sound a "sparking noise" or a "mechanical knock"?
Gary