SO pardon my ignorance. I just bought a 1979 Ford bronco with a 351M engine. I drove it home but the only way it would run was wide open and even then would cut out. I ended up giving it short bursts of wide open then letting off, then another burst, etc. SO I changed the spark plugs today, checked the fuel filter, ohmed out the plug wires and now I loosened the distributor. He is where my ignorance will show. I hooked up my timing light (I have never used one before by the way) and pointed it at the triangle thing that I am assuming is the timing point. i few inches towards the ground there is another bracket with a circle thing in it. What is this? The timing light showed two yellow lines on the engine damper. The gap between the two lines seems to match the lower bracket. Is that bracket supposed to be in between the two yellow lines or is one of those line supposed to line up with the triangle bracket? And if so, which one?

I moved it around a few times and tried a couple different spots and the engine def sounded different but I figured I better figure out the RIGHT way to do this. Truck is completely stock.

 

Maybe this will help.