E3 Spark plugs any good?

[Frank Wyatt]

I am going to throw my $.02 in on this one (FWIW). I found in running a tune up and carburetor shop a lot of interesting facts. First "gimmick" plugs, they may help, but usually just the fact that they are new is most of the improvement. Second, anti seize, I use the nickel base one on aluminum heads, generally not on iron heads.

For those of us who have other than just Ford trucks, plug sourcing can get interesting. OEM for US manufacturers were AC - GM (they own them), Autolite - Ford until they were sold, Champion, Chrysler and AMC. Ford now calls for Motorcraft.

Plug numbering systems can be a real can of worms, for years they were alpha-numeric, the alpha portion identifying the basic geometry and the numeric the heat range, lower = colder, higher = hotter. Examples - BF42, Autolite plug for most Ford V8s from the Y-block through the early 429/460 engines. BF32 was colder (My Shelby used them) BF82, much hotter, most 6 cyl Fords for years. Champion N - Nash, long reach (3/4") J - GM mostly, short reach (3/8") H - Hudson, plug used in many Onan built engines also. AC plugs use a reverse sequence with the number first then the reach letters, 44F, fairly hot, 3/8" reach, 42F a bit colder. 42FF Corvair .472" reach, same plug as a VW Beetle air cooled engine. AC stopped making the FF plugs in the late 90s, saying to use the F plugs, problems caused are the inner end of the plug is slightly recessed into the threads.

Plug reach, and tip design (projected vs flush) can make a huge difference in engine running, Two personal examples (not mine, but friends vehicles) Bosch platinum plugs in EFI Fords = poor running, erratic misfire etc. Don't ask my why, it was on several 302 EFI engines. AC plugs, correct heat range and reach by the catalog, 1994 F150 5.0L, abysmal fuel economy, owner had inherited the truck as a payment for administering his neighbors will. He pulled the plugs and found the ACs, put Motorcraft ones in, damn near doubled his gas mileage. He called me on his cell from I64 on his way to his retirement home he was building and started singing "I'm a believer" to me. He was already beyond Richmond from Newport News with a load of material and hadn't even used 1/2 of the first tank where before he would have been switching tanks by then.

I had the same problem with the Bosch plugs as well on a 302 in a '79 Couger XR7. I put them in and drove it up the road to the next driveway and back and put the Autolite's back in. They did show me the Autolites still had a lot of miles left in them. The 302 sure did not like them and I have never tried the Bosch plugs in anything ever since.

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