65-70 Shelby Autolite Sparkplugs

[Bob Gaines]

My '69 Ford shop manual, page 08-08-04, shows "BF-32" for all applications of the 351-4V engine. My '69 Cougar owner's manual also shows "BF-32" for the 351-4V. But the '69 Shelby owner's manual shows "BF-42" for the GT350. Typo, or did Shelby really spec a different plug for the GT350? Seems unlikely, but I'm sure someone will enlighten me if that's the case.

If it was a typo then it was one to the advantage of the owner given how frequently the BF 32 fouled out compared to the BF42 in city stop and go traffic. They are retaliative easy to change on a smallblock but I hated to frequently change those hard to get to plugs on my GT500 back in the day when it was daily transportation.

[cj750]

My '69 Ford shop manual, page 08-08-04, shows "BF-32" for all applications of the 351-4V engine. My '69 Cougar owner's manual also shows "BF-32" for the 351-4V. But the '69 Shelby owner's manual shows "BF-42" for the GT350. Typo, or did Shelby really spec a different plug for the GT350? Seems unlikely, but I'm sure someone will enlighten me if that's the case.

If it was a typo then it was one to the advantage of the owner given how frequently the BF 32 fouled out compared to the BF42 in city stop and go traffic. They are retaliative easy to change on a smallblock but I hated to frequently change those hard to get to plugs on my GT500 back in the day when it was daily transportation.

An advantage unless the hotter plug causes ping and detonation. The avoidance of which being, to the best of my knowledge, why Ford typically specified the cooler running BF-32 in high-compression engines in the first place.