I have a 74 360, when I am driving at steady speeds,or slightly accelerating, I encounter an erradic miss. I thought that it was the carb, I have turned every screw on the thing twice with no changes. Now I am wondering if it could be a weak ignition system.
at the time I am stuck with a crummy points type dist. I have a new set of points,condensor,cap,rotor,plugs,wires,ect.. now I am wondering about the coil. is there a way that I can check the coil to see if it is putting out enough juice? if so, how would I do it and what kind of readings should I look for?

 

Do you have the positive and the negative reversed on the coil? I've heard of that allowing an engine to run but not run well. also have you ran a compression test?

 

the engine has been rebuilt recently. I did a compression check, if I remember right it was 135 straight across the board. as for the coil being reversed, I will have to check that one tommorow. I just hooked it back up the way it was before I rebuilt it.

 

I just re-learned a lesson about spark plugs. I had discovered that certain engines needs certain spark plugs. My recollection is a little fuzzy about the specifics of the vehicles, but I do recall that changing Champion spark plugs for some extended tip Autolites made all the difference in an older vehicle, probably a Dodge.

Yesterday I ran into the same thing with my 54 F100's 223 engine; two plugs were misfiring. There was a new set of Champions in there. I substituted two Autolites in the misfiring holes and, wah-lah!, misfire gone.

 

I'll pass on a lesson I just learned. After rebuilding my 390 it ran well for a couple hundred miles then started missing bad. After tweaking it for 2 weeks with no improvement I asked on the '67-72 board and was told to make sure the coil was making good ground. I sanded the new paint off the inside of the coil bracket and also the place where it mounts to the manifold. It runs great.
I'm no electrician, but obviously (now anyway) the coil needs to contact the block to make a circuit.
I think its like this:
The primary circuit: battery - key - coil - points - ground - battery,
Secondary circuit: coil - dist cap - rotor - plugs - ground – COIL
And I think they are electrically separate, the way the secondary gets its power is the primary winding in the coil acts just like a generator to produce a magnetic field that charges the secondary windings.
Yada Yada

Mike

Of course I could be wrong...