1986 351w timing mystery solved
 

I'd posted last week about not able to time my truck. I did find the timing scale on the harmonic balancer, took a wire wheel to it but still couldn;t quite make it out, so put yellow nail paint on it-seems now to be about 5-10 ATDC with the vacuum tube the the dissy advance removed, idling about 900 rpms. Truck says 10 degrees BTDC on the radiator support.

Once I free up my dissy, I will retime it...hopefully smooths it out some...and maybe helps my mpg?