Recently came across a couple BF-32 variants I had not seen before so thought I'd share my observations, and start a new thread to add to this discussion, https://www.saac.com/forum/index.php?topic=9326, but focus on plugs available in 1965 and later thru the end of Autolite versions. I assume these variations apply to all Autolite plugs, not just BF-32's. I've not seen any documentation describing these changes so the evolution proposed here is entirely my opinion based on what seems logical to me.
Variant 1: Typical star logo plug. Most noticeable feature is the long electrode measuring ~0.11" which is also seen in the earlier 3-rib plugs mentioned in the above thread.
Variant 2: Same as variant 1 except the electrode is much shorter, measuring ~0.07". All plugs going forward have this same shorter electrode.
Variant 3: Same as variant 2 except the star logo has disappeared and that area is now blank. I remember Randy Gillis, RIP, mentioned seeing these as early as very late 1966.
Variant 4: First Powertip variant. This is the only one like this I've personally seen. 'Autolite' and 'BF32' text appears the same as variants 1-3 except 'BF32' is moved to the opposite side and 'Powertip' is now added beneath 'Autolite'.
Variant 5: Most commonly seen Powertip variant. Larger font 'Autolite' text on one side, 'Powertip' and 'BF32' on the other.
Variant 6: Late Powertip plug produced shortly(?) before Autolite and Ford went their separate ways, box has both Autolite and Motorcraft wording. Different/smaller font 'Autolite' text, slightly smaller 'Powertip' and 'BF32' text. This is the last Autolite version I'm aware of. After that the BF-32 was Motorcraft and the equivalent Autolite became #34.
There are other differences as well such as, the knurling pattern in variants 1-4 is much more pronounced than 5 and 6, also 'Made in USA' text placement to name a couple.
(https://www.saac.com/forum/gallery/236-180824135027.jpeg)
Nice reference, thanks for posting. The linked topic is very informative with Dan's details.
Great information! Now I am curious to see where the two boxes of plugs I have fall into this variant line. It never ceases to amaze me how subtle changes occur through the years.