Breathing new life into the 318 in the Scamp!
Popped the inspection window on the dust shield and checked all four. Nothing loose. The frequency, pitch and volume against the idle sound like a rod knock. It's consecutive to the RPM of the engine and I'm sure if I didn't care about parts and started pulling plug wires, I'd find it, but I don't want to risk hurting anything else.
I think I'm just going to gear up a forged crank that I have access to and it's matching rods to do a swap with new bearings and a fresh turn and polish.
I think that will be the least expensive and quickest way for me to get this back up and going.
If I don't run the engine anymore, I think I can keep track of the lifters, piston assemblies and get it all stuffed back under the hood as soon as I have another crank and rod set ready.