Should probably mention here that there seem to have been at least two and maybe three different series of AC Rapidfires. The first series was mostly conventional except for a ribbed electrode. These are easily recognizable by ribs in the porcelan. A few years ago these were slipstreamed to a platinum pin electrode and the porcelain is smooth. This happened sometime around 2001-2002 and for a while it was possible to get either or both when buying a set, there were only minor changes to the box. (need to check if buying at a flea market).

The early Rapidfires were pre-gapped and came with a plastic protector around the electrode, later ones require gapping but should not be changed over .010".

As far as I can figure, the only difference between the #3 and the #14 is the basic gap: #3 which I would suggest for a Magnavox ignition is .045" and the #14 which I use with the Delco is .060". Keep in mind that the wider the gap, the more stress there is on the rest of the secondary ignition so for an .060" you should also have at least 8mm plug wires in top shape.

I just got done with the Delco swap-easy! Total cost was a whopping $24.99 from a local junkyard

A great big thanks to all who supplied info on this, you all rock! The car does start a little quicker & idles smoother. My old Magnavox had just over 250K and was original, so this has to help out. I'll let you all know if theres a gas mileage improvement.

Just a quick mileage update-I'm still shocked. I got 26.5mpg this last tank of gas, after the Delco swap This car has never been anywhere near this high, its usually right around 18MPG. I have been driving a lot easier to save gas, but that alone was not the reason for the high MPG. This is in a car with over 250K on the ticker! It does run noticeably better too.

Gramps-did you do yours yet?

OK you guys motivated me to get the Delco Ignition just on the mileage numbers alone.
I'll put it in when the spirit moves me. Trouble is I have a good working magnavox with blue streak coil and it starts on the dime and runs smooth.
Is that MPG improvement on combined city/highway driving?
Cause thats what I get around town about 18.

I installed mine about two or three weeks ago, so far the gas mileage is up about 1-1.5 mpg. BUT, my car had a miss, the old magnavox was going out on it. There are plenty of good things to enjoy about the ignition already discussed... but don't count on significant mileage improvements.