Some of us have run into a problem with clearance between header tubes and a spark plug on our motors with aluminum after market heads and our headers of choice.

In my case I have AFR 190 'straight plug' street heads and Hooker Super Competition Long Tubed headers. My plug #7 would not fit, period. The others were fine, plenty of clearance. I did not want to dimple the headers, this would degrade performance a bit and void the header warranty (big deal!).

For me though, I wanted the solution to be with the spark plug. I called Accel and they will market a shorty plug for this application sometime next year. According to AFR, I need a 14mm, 3/4" reach, gasketed type spark plug. I can't wait for Accel so I took a new AC Delco FR3LS plug and removed the boot tip and ground the ceramic isolator down in length about 3/8"-1/2" using a table grinder. I then modified the length of the tip and reinstalled it back into the isolator.

This new plug is very short and works fine in the cylinder. It may not have the exact same electrical properties of the original plug, but it works fine and eliminated my electrical arcing problem as well as the fitment issue.

I have high temp plug wire and boot sleeving that help too.

I used the Mufflex y-pipe for my install. It is tight to the bottom of the car but fits fairly well. I'll run the y-pipe (3" to 4") by itself at the track and I have a 3" Dynamax bullet muffler with a 4" to 3" coupler that I'll use on the street that exits before the passenger rear wheel. Sounds nice!!

I also had my Dad (Machinist) make me a very short spark plug socket to get to all my plugs. It fits over the plug, with the tip protruding, and uses a 3/4" wrench to loosen/tighten plug. It works great. If you want one he'll make some more for you guys for $8-10 a piece shipped to your door! Just email me if interested.

Take a look.............

http://www.geocities.com/cfrios/Phil...l?996948051310


[This message has been edited by Phil87IROC (edited August 09, 2001).]

[This message has been edited by Phil87IROC (edited August 09, 2001).]

[This message has been edited by Phil87IROC (edited August 09, 2001).]

 

Thats pretty cool, good idea there. I hope it works out well. Some of my wires/boots are pretty close to my headers, and Im close to firing up the engine for the first time.. What kind of clearance do you need with ceramic coated headers?

 

Not sure since mine are not coated. I regret not having that done. When I use the high temp sleeving over the plug boots I can have them as close as 1/4" and not worry too much. Without the sleeving I need way more clearance, like an inch or more. BTW, I use MSD 8.5mm wires and boots.

Good luck!

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Phil87IROC
Blue '87 IROC, 383 Crate Motor, KB pistons, AFR 190 heads, TPIS ZZ-9 cam, Edelbrock RPM intake, 1" TD spacer, Hooker SC/LT headers w/ Mufflex Y-pipe, Edelbrock 750 cfm Carb (#1411), Stock T-5, GM 3.42 gears w/Auburn posi.
Ohio Valley Dragstrip (KY) Trophy Bracket WINNER - 8.39 ET on a 1.82 sec. - 60'. Best MPH = 84.44. Still Tuning Carb!
Red '89 IROC L98, TES w/Flowmaster, 1LE DS, 700R4, T-Tops, K&Ns w/open air boxes, 160 T-stat, Hypertech Chip, gutted MAF & CAT, Jacobs Ign., 53kv coil, MSD wires.

[This message has been edited by Phil87IROC (edited August 09, 2001).]

 

TTT, just in case anyone interested in this would have a chance to see it.

Thanks.........

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Phil87IROC
Blue '87 IROC, 383 Crate Motor, KB pistons, AFR 190 heads, TPIS ZZ-9 cam, Edelbrock RPM intake, 1" TD spacer, Hooker SC/LT headers w/ Mufflex Y-pipe, Edelbrock 750 cfm Carb (#1411), Stock T-5, GM 3.42 gears w/Auburn posi.
Ohio Valley Dragstrip (KY) Trophy Bracket WINNER - 8.39 ET on a 1.82 sec. - 60'. Best MPH = 84.44. Still Tuning Carb!
Red '89 IROC L98, TES w/Flowmaster, 1LE DS, 700R4, T-Tops, K&Ns w/open air boxes, 160 T-stat, Hypertech Chip, gutted MAF & CAT, Jacobs Ign., 53kv coil, MSD wires.

 

Thanks, I think Im going to be getting some sleeving just in case..

 

I've seen short plugs a Auto Zone. Just a little FYI.

 

ATO,

I've seen many shorty plugs around town and online. The problem is finding one that's a 14mm, 3/4" reach and gasketed. They are for AFR 'straight plug' aluminum heads. If you are there again soon, can you see if they have a set that meets this criteria?

Thanks!

[This message has been edited by Phil87IROC (edited August 13, 2001).]

 

Sounds like you did some impressive work there getting all of that done. If I run into any problems on my car I will keep you in mind.

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84 Z28 383
Stripped w/Cage back halved w/ladder bars and coil overs and 9 inch
700R-4 3.73