So i went to change my sparkplugs today to find the new ones didn't fit. Compared the two. Totally different reach. I double checked the store sold me the right plugs. So now if left wondering, is my engine what its something to be or is it something different. Or someone just changed the heads. The plugs in it was Champion rs14lc that plug fits http://www.championsparkplugs.com/re...asp?pid=rs14lc

So is there anyway to id my head or engine. Its got the 92 intake

 

There should be casting numbers on the heads. It's possible that you have GT40 heads. If you do, then the spark plugs are Motorcraft # AGSF-32C. One of the gurus might have a list of casting #'s.

 

What makes you so certain that the engine currently has the correct plugs?

The simplest answer is often the correct one. What if at the last tuneup someone put in the wrong plugs?

Forgot to mention, you cannot read SBF casting numbers with the heads in place

Look here: http://www.aacncclub.com/FORD_HEAD_CASTING.html

 

What plug does your parts store think you should have? You never posted that number. The only reference I took time to look up showed a RV15YC4.

http://www.championsparkplugs.com/re...p?AAIA=1122039

 

Autolite 25, The reach is like 1/2 too short. Plus the new ones don't thread. And i can't see someone forcing spark plugs into a head. Plus wouldn't the piston hit the ends if they were 1/2" too long.

 

The Autolite 25 crosses over to a Champion RV15YC4 which is a 14mm, tapered seat .460" reach plug, exactly the correct part fot a 302 truck application.

The ones that were in it, if I'm following you correctly here were RS14LC, That is also a 14mm tapered seat plug except that it has a .708 reach. Other than a .248" reach the two plugs should be physically the same. The RS14LC is used for some 5.0 (non-HO) automotive applications.

But you're now saying the new plugs won't even thread in? What am I missing here?

Do your heads appear to be original? Look at the paint color where they mount on the block. Is it the same on both sides of the head gasket? Does it appear to be continuous across the joint in at least some places? If so the stock heads have never been off of it and someone has previously tuned it up with the wrong plugs.

 

I live on the Northeast coast, Everything has surface rust, to compare. Try as hard as i can on two different cylinder i can't get them to thread. The old plugs go in & out fine. Also this truck was wrote-off some where's down the line ( i know this because what it says on the permit) The valve covers are the only thing with some paint left on them & there blue say "Ford" Im just going to have to buy the autolite's 2545 and run those. because these won't thread for what ever reason

 

The 2545 is a 14mm thread, tapered seat, .708" reach plug. If it threads into the hole, then so will the ones you have now. The only difference is reach. Your truck's original engine was set up for the shorter reach plugs. It probably still is.