Thanks for all the feedback.   I've been resistent to diving back in to the timing set with the hope there was something simple.  But consenses seems to point to the timeing gear.   The first sugestion from a local mechanic was to check the valve adjustment.  He also thought the intake valvels were staying open too long and the air fuel mix was being forced back through the intake.  I checked my valve adjust by "finger twisting" the push rods at the bottom of the cam lobe.  All looks good there.  Thank God for that 2-piece timing cover!  I'm goin in.

Thanks again.