Timing Retarded

I adjusted the bottom-end tab (It was extreme to the right, I moved to the middle of the slot), then went through normal process to set distributor position. Used compression guage in cyl 1 to see compression stroke, stopped at TDC, set distributor so it's at position 1. Actually played with the position and watched the point spark.

No good, won't run! Tried half a dozen times, 10deg before, original position of the bottom tang, different combinations. You can hear it trying but something's odd about the pattern of fires.

Looking back, I should have put it at cyl 1 TDC and marked rotor position before I took it out. Silly me, I was trying to do things by the book!

At this point, I'm really suspicious that the last mechanic did some voodoo with the distributor to adapt for a skipped chain. When it was running, the most advanced I could get it was 2 degrees after but I could pretty much retard it as far as the distributor would go. I know the cylinder is at TDC when the HB wheel mark is at 0 because I can put an unsharpened pencil in the plug hole and the piston is right up there.

At this point I need to verify timing chain position; I know I should be able to do this by watching the lifters. Any good threads about that technique? Any suggestions before I abandon the ignition system as the source of my problem?

Thanks folks,