MSD 8mm (Discount Auto Parts) wires & Autolite PN45 Platinum spark plugs.

Doing Fords for 45 years. '56 Customline Victoria

E.J. in Havana FL

Hi Richard,  The NAPA guy is correct that the stock Autolite plug for a 292/312 is their #46.  BUT- the Autolite #36 is exactly the same heat range, but it is a non-resistor plug.  The #46 is a resistor plug, of course.  Their #45 is one step colder, should work fine with your compression ratio.  Here are some other plugs that are one step colder than stock:  Accel 375/ 675, Champion 22/ RF11YC, Motorcraft 420/ BSF42CF4.  Personally I would skip the resistor plug caps and use a fiberglass core resistor plug wire, works for me.  Measure the resistance with a VOM from one end of the wire to the other, shouldn't be more than 1,000 ohms per foot.  If more resistance than that, the wire is worn out or defective.  Good luck, Nick Brann - K.C., MO

Performance Distributors Distributor, ignition box, LiveWires, and Inferno coil with the NGKs.


Lawrenceville, GA

  Also running Autolite 45's with a MSD #8383 Dist. and 8mm MSD Street plug wires and lites her off every time!  KID

46s 55 bird 292 113 heads Taylor wires doing fine  about 5 years

55Birdman  Hickory NC

I have to quantify, compression is a little over 9 to 1. After looking through the search engine here it looks to me like a NGKWR51x iridums would be the best plug, however since they are expensive and the engine will be fresh in need of tune, I think buying the Champion 22 (RF11YC) as well may be prudent. The connectors I am using are NGK resistor connectors with screw in wire for the solid core and require a plug without a tip cap. The auto lites tip is fixed/ won't screw out.

Any advice is appreciated. Cracked insulators don't sound good, not sure thats a heat range issue.



Richard



PS Pictures to follow soon

Currently running AL 45s (292/113 heads). Still getting insulator cracking on some cylinders.

6 VOLTS/POS. GRD. NW INDIANA

Hi Gang,

I wanted to find out what you guys are running for spark plugs. My 312 has pocket ported heads ala Mummert, a mild Clay Smith cam, a vintage Mallory Dual Point ( I know what your gonna say, but I wanna build a unit some what from the era ) I was planning on 7 mm solid core wires with resistor plug connectors. I had bought a set of Auto Lite 36 plugs a while back but these maybe too cold. The Napa guy said stock 312's call for an Auto Lite # 46. Carburation at first will be a Holly Dbl Pumper 600 cfm on a hogged out 57 manifold. Later I plan to switch to 3 twos. Any suggestions are appreciated.

Richard