TheGeneral Posted February 14, 2022 Share Posted February 14, 2022 Hi everyone, 1985 F150/2wd/manual/stock ignition, inline 6 here. I am doing a tuneup. After 2x tuneups with Autolite copper cores I am trying to find the right Motorcraft plugs to see if I can notice a difference, but I just realized my Chiltons has a different plug than what I am told I have to special order at all three local shops (SP-420A I think) From what I have read regarding the topic: 1.) most people who know their trucks well, say the Motorcraft coppers are the best for the inline 6 (assuming stock ignition/distributor) 2.) some people use a plug that goes a little deeper into the engine for better combustion (I am willing to try this) 3.) some people use a Motorcraft plug for the EFI's on their carbed engine, just fine. hopefully all reasonable? So, Chilton's 80-96 (ugh) specifies "BSF44C or equivalent", yet online auto parts stores say this will not fit my vehicle! Does that mean it's for the 87 and up EFIs? The only thing close I can find that's Motorcraft is "BSF44CA" (local Autozone) and the reviews are people with 89/90/95 trucks! I'm confused. Sure would like to buy and try... Is this a matter of threads/hex dimensions? I can't find much info. Thanks for anyone that chimes in. Cheers, Bell Link to comment Share on other sites More sharing options...
85lebaront2 Posted February 14, 2022 Share Posted February 14, 2022 What does the emission label say for spark plugs? For example, Darth's says ASF-42 gap .044-.046 Link to comment Share on other sites More sharing options...
TheGeneral Posted February 14, 2022 Author Share Posted February 14, 2022 What does the emission label say for spark plugs? For example, Darth's says ASF-42 gap .044-.046 "BSF-42 / .042-.046" why do I always forget to look at my labels?? TY Link to comment Share on other sites More sharing options...
TheGeneral Posted February 14, 2022 Author Share Posted February 14, 2022 "BSF-42 / .042-.046" why do I always forget to look at my labels?? TY I see, the BSF-42 is now the SP-420 I have been told I need and is not local... So, next question would be, would I be able to use the 87-up EFI type copper plug, and would it improve performance at all? I am trying to rule out poor quality spark plugs for a bit of stumbling I have... Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 14, 2022 Share Posted February 14, 2022 I see, the BSF-42 is now the SP-420 I have been told I need and is not local... So, next question would be, would I be able to use the 87-up EFI type copper plug, and would it improve performance at all? I am trying to rule out poor quality spark plugs for a bit of stumbling I have... I think David changed to the later plugs, so I'm going to tag him. Link to comment Share on other sites More sharing options...
TheGeneral Posted February 14, 2022 Author Share Posted February 14, 2022 I see, the BSF-42 is now the SP-420 I have been told I need and is not local... So, next question would be, would I be able to use the 87-up EFI type copper plug, and would it improve performance at all? I am trying to rule out poor quality spark plugs for a bit of stumbling I have... http://vb.foureyedpride.com/showthread.php?186716-SP450-vs-SP450A mb757 had the following information regarding spark plug naming convention! Super helpful. "The long part number on the spark plug from Motorcraft will tell you quite a bit about the plug itself, for example ASF-42-C breaks down with the ASF is the seat and thread size ASF is a 14MM tapered seat, BSF is an 18mm tapered seat, AGSP is a 14mm gasket style seat. The 42 is the heat range a cooler plug would be a 32, 22 and so forth, a 44 would be the same heat range with an extended tip. The suffix of a C would be a copper core, P would be a Platinum, and a FM would be a fine wire platinum and so forth. I like to use the long number but the short number causes much less confusion and your chance of handing out the wrong plug are a lot less." Link to comment Share on other sites More sharing options...
1986F150Six Posted February 14, 2022 Share Posted February 14, 2022 I think David changed to the later plugs, so I'm going to tag him. This is what I used for many years: https://shop.advanceautoparts.com/p/motorcraft-spark-plug-bsf44p-sp-452/18090030-P Link to comment Share on other sites More sharing options...
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