Spark Plug Discussion/help

bdep73

Member
Jan 15, 2012
31
1
8
hartford, CT
hey guys I need your help. This is a bit more technical than me wanting to know what plugs to use. I have 1990 5.0 that the previous owner had a Ford reman engine installed at the dealer back in 2003. I recentlly installed a Novi 2000 on the car and went to install new spark plugs one range colder. the issue is the plugs I pulled out of the car are the Motorcraft AWSF-44C which have a .708 reach and only fit the 1986 5.0 with flat top pistons. The plugs that belong in a 1990 5.0 are the Motorcraft ASF-42C which have a reach of .460 and are for the E7 heads. Fortunatlly the previous owner kept good records and had the invoice from the dealer that installed the engine and the dealer used the AWSF-44C plugs when they installed the engine. The engine is the F1ZZ-6V012-BRM that if you did a look up on Motorcraft's website is supposedly for the 89 - 93 mustang.

I am trying to make this as short as possible so please bear with me guys. I called the dealer and asked them why the plugs on my car are for the 86 5.0 which has different heads and flat top pistons. I was hoping they could tell me what heads are on my car but they were not able to help me. the dealer gave me the phone number to Fords powertrain division I gave the tech guy the engine part number, serial number and after an hour on the phone we got nowhere. It amazes me that Ford has no information on an engine that they still sell to this day. The tech guy said he would speak with the engineers and get back to me bu tone of his last emails was to ask me if I could give him the casting number from my heads which we all know is no easy task.

I attached a photo of the Autolite equivalent plugs. the plug on the left (Autolite 2545) is the longer one that came off the car and the plug on the right (Autolite 25) is the plug that should go on a 1990 5.0. The last email I got from the ford tech guy was to ask me if I actually tried to install the correct plug for my car and tried to start the car or if I just compared the two. correct me if I'm wrong but if I waste my time and install the Autolite 25 plugs that are .258 shorter the car won't start. Any suggestions on what heads I might have or any other info would be greatlly appreciated.




new 008.jpg
 
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that 44 is a hotter plug car will start with either plug. you don't have them side by side. put them side by side at the shank ie bottom of thread not the nut..looks to be 2 steps cooler. do you have a MSD or the type of ignition?
 
that 44 is a hotter plug car will start with either plug. you don't have them side by side. put them side by side at the shank ie bottom of thread not the nut..looks to be 2 steps cooler. do you have a MSD or the type of ignition?





I'm not sure what you are looking at but they are side by side thread to thread and the autolite 2544 would be a colder plug than the autolite 2545. The lower the last digit on a Autolite plug the colder. you are thinking of NGK they are higher number colder plug. Also the 25 is just that 25 no other numbers and that plug does not fit I tried it today.