Had To Get Autolite 2546 For A 88.

billison

I like tinted tail
15 Year Member
Feb 27, 2006
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had to replace a cracked spark plug. The autolight 25's would not fit. Had to get 2546 , that comes up for a 86 model... good guess my motor or heads were downgraded...
 
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Is it fuel injected or carbed ? Our cars get so cjpped up its hard to tell what the motor came out of unless you get the casting numbers off the block and heads.
 
A couple pics comparing the type I have vs what seems to be the normal plug. The normal plug does not have the extra crown after the threads and has a thicker body that would not let it fit my cylinder head.
 

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Instead of making a new post I figured I'd ask here.

Ok, so the difference in plugs makes me think I do not have the stock e7 heads. I'm now worried I have a older flat tapped motor... is there a easy way to
Check this?

And is there a way to check the heads without pulling them?
 
Instead of making a new post I figured I'd ask here.

Ok, so the difference in plugs makes me think I do not have the stock e7 heads. I'm now worried I have a older flat tapped motor... is there a easy way to
Check this?

And is there a way to check the heads without pulling them?

From DIY porting:

e6spark.jpg
E7sparkhole.JPG

About the only easy way known to modern science to identify an E6TE casting is to inspect the spark plug hole. Here, there is a decernable difference.
The photo on the left is a close-up of an E6TE spark plug hole. On the right is an E7TE spark plug hole.
Look closely and you can see that the E6TE spark plug hole has a deep recess from the casting surface to the plug threads, while the E7TE spark plug hole does not have the deep recess from casting surface to plug threads. This difference in the spark plug holes is the only 'practical' way I know of to identify an E6TE from the exterior.
 
Passenger side bottom-front corner of head (near #1 cylinder) OR driver side bottom-rear corner of head (near #8 cylinder), outside of valve cover rail...
GT = GT-40
P = GT-40P
R = E5AE
S = E6SE
T = E7TE
 
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Ok. Bumping a old post. While I was under the hood today I checked the heads for stamps and found an S. This confirms that I have E6 heads.

At this point I’m trying to figure out what that means as far as the motor. This means I might have an 86 block and flat pistons right? So I need to get my scope in there and look at the pistons.
 
Could be a H.O. or a S.O. engine. They both used the same E6SE heads in 1986, and continued using them on S.O. engines after 1986.

You'll need to get the engineering ("casting") number and date code from the block to know when it was cast, or even better the VIN from the block to know what the engine is from. Of course that's just the bare block. The internals could have been changed.
 
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We got ourself a bona fide mysterious circumstance . Popped the scope in the plug hole and those sure don’t look like flat tops to me. I couldn’t get the scope to look up so that’s as far as I got.

The guy I got it from said it was rebuilt at some point and had a b cam. It definitely idles like it has a small cam and has a little pep.

I’ll gladly take more pics of that’ll help with the mystery. I have no plan to remove the intake or heads anytime soon, but will be swapping out my cobra intake for my gt40 maybe this winter.

As it stands, I’m gonna guess it was rebuilt and the e7’s were toast and they found and used these. He claimed they were ported but I doubt that.

Any suggestions for anything else I need to check?
 

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Lots of car on but definitely valve reliefs. Some guy on Facebook claims they are silvolite pistons but I dunno who he could tell from the pics.
 

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For now I’m just gonna leave well enough alone and focus on paint and getting it back on the road. I’ll post back here when I swap intakes with anything I find. If I ever start upgrading the engine, these heads will be the first thing to go.