the original coil on My '59 223 is weak. I have one on My shelf from a 1980 300 6 cyl. Could I use the coil from the '80 on My '59??

 

I would say no. The 80' should have been electronic ignition, so it ran a full 12 volts. Non-electronic used a resistor to drop to 7 volts to save the points from burning up.

Its possible it might work, but it would be very weak.

 

How did you determine the coil itself is weak?

 

Ford used the Duraspark II from 77-84. Ignition coil had the resistive wire still wired inline from the run side of ignition switch. So yes, it will work. Difference being the coil used a horseshoe style connector instead of regular posts.

 

Had secondary and primary restance checks done, had very weak,yellow spark

 

Interesting, what are the primary and secondary figures as measured? I bet the secondary has some shorted turns. Check plug wires carefully for proper resistance or replace, don't want to roast replacement coil.

 

Exactly. High secondary resistance is the most likely cause of coil failure, though not the only one.

 

Plug wires,cap,rotor points and condenser are all new

 

Good plan. What did the coil measure, though ?

 

Yes but the damage was probably done before.
On these old trucks, it's a good idea to check the resistor wire from the switch. Many times it's been scabbed into or butchered. You can still get new ones. I got one a couple years ago from NAPA for my roadster because I hate those problematic porcelain ones and wanted to keep my original 1963 coil.

 

B6A-12029-B .. Ignition Coil (Motorcraft DG-5).

All 1956/73 & 1974/75 I-6 & V8 without DuraSpark electronic ignition.

1974's with DuraSpark use a different coil, same coil used on 1975 F100/350 before serial number W00,001: D5PZ-12029-A (Motorcraft DG-313-A).

1975 F100/350 from serial number W00,001, 1976/87 all use a different coil: D5AZ-12029-A (Motorcraft DG-314).

 

Switch to electronic if you don't care about originality and want reliability. Not that hard. Even I did it.