I'm not a novice....nor an expert, either, but I've built a flat head Ford, or two, in my day. At 75 years of age, you'd think I would have observed the following before! Recently, I was rebuilding a '49 239, when I noticed, for the first time, that the spark plug threads in the heads are deeper than the threads on the spark plugs listed for my engine! (Champion H-10) Screwing an H-10 into a removed head, I can see there's approximately 1/8" of exposed threads in the spark plug hole in the head. Even torqued down, the tip of the plug is up, clear of the combustion chamber...the electrodes are shrouded by the threaded hole! I would think that the tip (electrodes) should exposed in the combustion chamber. Have some of you, who are a lot more experienced than me, noticed this and perhaps chosen an alternate spark plug, with the proper heat range and deeper threads? Inquiring minds wanna know!
Nope, Tubman, take your choice....I'm too stingy to buy 'em, or don't think they are that big an improvement for street use. I've had several flat-heads; all but one had original, mildly milled iron heads on it.. The one with aluminum heads ran fine, but the almost insignificant improvement in performance didn't seem to warrant the expense. Now, if I was doing some serious drag-racing, with a highly modified engine, maybe Aluminum heads would be called for. Thanks for your reply Tex, I'll check into Fordbarn. It just seems wrong that the electrodes don't extend into the combustion chamber! I think I've got enough room to avoid the electrodes hitting the valve below.
The Jalopy Journal
