workin on the gramps truck it is an 84 w350 with the 360 the harmonic balincer went to poo put a new one on (put two differnt ones on same problem) when i went to time it it was at 30 deg not likely would it run but it was. when i timed it to 6 ran like poo. timed it to 35 ran really good just rough idle. chain seems to have a little play but not much the cap and rotor are firing on the very end of the post not in the middle. Any toughts would help. nothing knowen of what was done before today on the truck.

 

Where are you getting your replacement harmonic balancers and are you sure they are for the 360. I would check with a salvage yard to see if all 360 balancers are the same.