Yeah Bruce, I'll do a compression test but I have a feeling all it will show is that a bad case of old motor has set in... After doing some research I'm 99% certain it's a combustion knock from carbon buildup in the chamber. The old plugs have oil buildup from leaky valve guides and I think there's got to be carbon buildup in the chamber. I think I'll nurse it through the summer (the Pac-Northwest All-Chevy Show is coming up and I already paid the admission) and then pull the old dog out and get it rebuilt.
Thanks guys for the inputs!
