funny thing happened while changing my plugs

[1987LXragtop]

So, a just over year ago I did the 5.0 swap into my vert. I bought the engine from a guy for a 100. I figured for a C note you almost couldnt go wrong. He was insistant that I did not need to open it up at all and that I could drop it in and go. It had been in a street rod and was carbed at the time. For some reason I believed him(I know...someone wants to sell me a bridge too) but I put it in, took the Weiand carb intake off and sold it on ebay for 125. and sold his father my 2.3 for 50. So I had a motor for free plus 75 bux. XXX stamped HO firing order all good. Swap in the efi, start it and it runs flawlessly no smoke smooth. great! I checked the plugs before I installed it and they were good and clean and never changed them.
Flash forward to now. find that number 4 isnt firing. I check and see that the plug is cracked. Not thinking, I go to Pep boys and they give me autolite 25s. People have their preferences Ive never had issue with Autolites. Get em home and start with number 4. Cant get it in ...wont thread. So I look at the old plug. Autolite 2544. So Im thinking, "WTF?" 25s are the number for stock HO motors. Now I want to know so I check the interwebz for a cross reference and find that 2544s would go in to GT40 heads.
So Im wondering if my deal was better than I first thought. I havent looked for a casting number because I didnt feel like disassembling anything. I know...long story to get to the end but does anyone know of other heads that those plugs would go into?

 

[SMOKEDYA]

I beleive the GT40 heads will have 3 bars on the face of them and are stamped gt or 40 or maybe both?I THINK like i said? peace







john

 

[1987LXragtop]

yeah i was trying to see those but with the brackets
for the accessories in the front I cant tell

 

[1987LXragtop]

Found a picture of the engine during install. No bars on the front. Damn. Now I want to figure out what they are.


edit: well the autolite 2544s cross over to Champion 407s which led me to a fitment chart. There were a few 5.0s on it most from crown vics or full sizes. The only one that I know to be a H.O is the 86 Mustang that they also fit. So looks like the whole deal is an 86 Mustang engine. Which means the swirl heads

 

[mob]

I have a reverse cross reference at my work and I can see all the cars that, that part number go in. I can check it out for you if I remember, If theres no bars on the front then its not a gt40 head. Most likely someone put the wrong plug in there. If those plugs fit a different 5.0 and if they had that motor in some other car there is a chance when they went to go buy plugs they just told the guy at the parts counter to get them spark plugs for any ford 302, and when the parts guy asked what the year make and model were they probably freaked out and told them all ford 302's are the same and to pick one, it happens to me ALL the time.

 

[NIKwoaC]

Haha, sounds like you got hosed. Here is a page that will help you identify the heads:

The Infamous E6TE

The '86 definitely takes different spark plugs than the '87-'93 cars. The '86 HO Mustang heads went on into service in non HO engines (Towncars and such) at the same time they switched to E7 heads on the Mustangs. If your luck is REALLY bad, you could have a non-Mustang 5.0, which would have a softer cam and maybe even cast pistons...

 

[1987LXragtop]

Haha, sounds like you got hosed. Here is a page that will help you identify the heads:

The Infamous E6TE

The '86 definitely takes different spark plugs than the '87-'93 cars. The '86 HO Mustang heads went on into service in non HO engines (Towncars and such) at the same time they switched to E7 heads on the Mustangs. If your luck is REALLY bad, you could have a non-Mustang 5.0, which would have a softer cam and maybe even cast pistons...

Well fortunately it is an HO firing order so Im reasonably confident that its an HO motor. So if I remember my HO motor history correctly then they are a higher torque but slightly lower HP motor with a lower redline. Higher compression with flat top pistons but the heads dont flow quite as well.+

Also sounds like I couldnt change the heads with out replacing the pistons to ones that have valve reliefs in them.

 

[Mustang5L5]

1986 gt came with those heads and the ho firing order

 

[NIKwoaC]

Well fortunately it is an HO firing order so Im reasonably confident that its an HO motor. So if I remember my HO motor history correctly then they are a higher torque but slightly lower HP motor with a lower redline. Higher compression with flat top pistons but the heads dont flow quite as well.+

Also sounds like I couldnt change the heads with out replacing the pistons to ones that have valve reliefs in them.

The '86 HO engine made 200hp and 285ft-lb VS the '87+ 225 and 300. The difference in CR is minimal, we're talking 9.2:1 VS 9.0:1.

It's a turd man, believe me, I know. Oddly enough, though, if you look at drag strip tests back in the day when these cars were new, the '86 stayed right in there with the newer cars. I think it's just that the E6 heads don't respond to bolt ons as well as the E7 heads do.

 

[1987LXragtop]

I guess I gotta look at it like this...Its in a vert so its really not a hard core car. Ive changed some things on the engine so Im curious even more now how it will respond as compared to a stock one. If for some reason it ever pops then its essentially a free motor anyway so 'll just pull it and build it the right way. I would be reasonably pleased if it was a low 14 high 13 car in its current configuration anyway.

edit: and theres always the giggle gas