Good evening, anyone running a set of original Autolite BF 32's in their K code?
Thanks, Scott
That's what I use in my 66 350. No issues, Nice uniform light tan color.
Same, no issues.
Yeah 2 GT350s with them in, no worries
I am running them as well in both GT-350's. No issues over the last 35 plus years.
Thank you all for the responses... can I ask where you've been able to find them? I have seen a set or 2 on Ebay here and there? Scott
Also, does anyone here run Pertronix as well? I was wondering if that's an issue running BF32 plugs with Pertronix. Last question, I do see a few sets for sale on Ebay as I mentioned and a wide range of prices... what's a fair price for 8 or 10 plugs? I see $1400 to $135?
Thank you all, Scott
Quote from: SCOTTGTK on May 28, 2026, 02:36:55 PMAlso, does anyone here run Pertronix as well? I was wondering if that's an issue running BF32 plugs with Pertronix. Last question, I do see a few sets for sale on Ebay as I mentioned and a wide range of prices... what's a fair price for 8 or 10 plugs? I see $1400 to $135?
Thank you all, Scott
The high prices are typically for the BF32 star marked plugs. Autolite marked BF32 are about 10.00 or more each .The BF32 Motorcraft marked plugs are less but I don't keep track of those.
I am using the Pertronix with 32s and OEM coil. Works OK in my cars.
Thanks Bob, trotrof1, any thoughts on differences between Autolite and Motorcraft?
Bob, I've seen star marked plugs, any difference in performance or were they star marked due to being older or newer?
BF42 might be a good option. A little hotter plug.
Quote from: SCOTTGTK on May 28, 2026, 06:07:25 PMThanks Bob, trotrof1, any thoughts on differences between Autolite and Motorcraft?
Bob, I've seen star marked plugs, any difference in performance or were they star marked due to being older or newer?
All BF32 are the same heat range just different in appearance. If you start to foul plugs or the tips don't look lean enough when you inspect them you can go to the next step up to BF42 as A-Snake/Jim suggested. A lot of us have done that over the years when we street drove the cars more.
I have a bunch of autolite BF 22 spark plugs. Does anyone use those anymore? Any particular engine use them?
Roy
Quote from: TA Coupe on May 28, 2026, 10:52:33 PMI have a bunch of autolite BF 22 spark plugs. Does anyone use those anymore? Any particular engine use them?
Roy
BF22's were heat range #3 IIRC, one range colder than BF32. Pretty much a racing only plug, don't believe it came factory in any production car.
Another option if you want to use BF32's is the Autolite #34 plug. After Ford and Autolite separated in 1972, all Autolite plugs got the Motorcraft name, Autolite continued making plugs with a new numbering system. The BF32 was now Motorcraft while the Autolite version was #34, same exact plug. You can find Autolite 34's cheaper than BF32's, here's a set on ebay now:
https://www.ebay.com/itm/127812391980 (https://www.ebay.com/itm/127812391980)
Quote from: s2ms on May 29, 2026, 01:50:38 PMAnother option if you want to use BF32's is the Autolite #34 plug. After Ford and Autolite separated in 1972, all Autolite plugs got the Motorcraft name, Autolite continued making plugs with a new numbering system. The BF32 was now Motorcraft while the Autolite version was #34, same exact plug. You can find Autolite 34's cheaper than BF32's, here's a set on ebay now:
https://www.ebay.com/itm/127812391980 (https://www.ebay.com/itm/127812391980)
Does the same hold true for the BF42 plugs?? Did they become 44??
Quote from: 68blk500c on May 29, 2026, 03:38:13 PMDoes the same hold true for the BF42 plugs?? Did they become 44??
The BF42 became the new Autolite #35. After a while the Autolite 34 and 35 were both phased out and replaced by the Autolite #45. Never used the 45's myself but have heard they work well in a 289 HiPo, same heat range 5 as BF42 and 35, the 45's are still available.
I think the Autolite 44 might have been a successor to the 34 (same colder heat range) but it seems to be obsolete now.
A few years back, I tried a set of the AUTOLITE 45's and found that they run on the cold side and have a tendency to foul. It all depends on your engine and how it's tuned. If yours is higher compression and/or has been bored out and tends to run hotter, they might work. Otherwise, pony up and get the BF32's.
Quote from: SCOTTGTK on May 28, 2026, 02:29:51 PMThank you all for the responses... can I ask where you've been able to find them? I have seen a set or 2 on Ebay here and there? Scott
https://www.ebay.com/sch/i.html?_nkw=Autolite+BF32&_sacat=0&_from=R40&_trksid=p2505460.m570.l1313
Thanks Royce... I'm checking these out also!
Actually the BF32 was obsoleted and replaced with the BF42.
The BF32's were recommended for the higher compression engines and the 42's for the lower compression engines.
Either will work but what you may find is that rpm's over about 5,000 rpm's are limited by the hotter 42 plug.
I know that there is a general dislike of the Champion plug. Not that they are inferior, but because that isn't what the "Kool people" run. However, that series offers a greater heat range then most others do, INCLUDING the Autolite's.
I have that using Champions to "tune" a brand new engine helpful.
The only other plug that comes close to that "tunability" is the NGK. If you look at the actual engineering heat ranges of their plugs, it will give you an indication why. The answer is, their design, gives a wider heat range for the same engine.
BF32's have NEVER been the exact right plug for the high performance Ford engines. They have ALWAYS been on the too cold range, noticibly fouling particularly with automatic transmissioned cars used in bumper to bumper traffic, whereas the 42 is too hot and causes detonation over 5,000 rpm.
The Champion can be dialed in better as is the NGK.
The Autolite tech guy told me to use AR33s, and they have worked fine in my 427 Medium riser. What NGK plugs would you recommend? NGK used to advertise "copper core" which worked better in two stroke motorcycles.
Any thoughts?
I have extra sets of NOS BF32's, BF42's, BF34's, BF35's and BF45's
Jon
Jon, how are you selling the BF32's and 42"s and do you have pics, are they in boxes? Thanks, Scott