HI all - I cannot update anything on this topic (perhaps because it is an older thread)
So - just a quick update. As someone (I think Dad) had suggested, the cam was toast. At least 2 lobes were ground down to smithereens.
So - after checking prices, being cheap, and retired with a fixed income, I decided to give it a go myself.
I have the engine out and have replaced the Cam, timing gears, chain, oil pump, and have rebuilt the heads with stiffer spring to go with a mild cam. I am in the process of re-assembly this week.
It will be awhile before it is back together as I have to do some snooping around while the engine is out. I'm learning a lot as I go along.....
The patient (or victim) is a '76 smogger, L-48 SBC.