Plugs/wires recommendation

Daryl

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‘95 Cobra coupe, 5.0L with 6lbs boost via SVO supercharger, 90k original miles, BBK 70mm throttle body.

I’m going to have the supercharger gone through, freshened up and repaired as necessary. In the meantime, I’m replacing the coil and distributor, and figured may as well do the plugs and wires too since I have NO idea how long they’ve been in the car! All that beIn said, I’m looking for input on what gauge wires(?) and specs on spark plugs appropriate for my application (?).

Preliminarily, I looked at NGK and Motorcraft (bit of a purist) but got overwhelmed with gaps, diameters, heat ranges, blah blah blah! So, I’m defaulting to your input and experiences for recommendations

Many thanks to all,
 

01yellercobra

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Why not pull one of the current plugs and see what they are? If they haven't given you trouble get a new set to throw in.

I thought 8mm was the standard thickness for wires nowadays? I haven't ran anything with plug wires in a long time.

I'm not sure how the push rods react to plug gap. For that low of boost I'd run .035-.040" in a mod motor.
 

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Has the car ever been on a dyno or has it ever given you reason to believe it’s having spark issues?? Usually you don’t need to close the gap until into a little more boost but generally that’s if your having issues with the boost blowing the spark out. Same with going a step cooler on the plugs.

This is why I ask if it’s been dyno’d or if it’s having noticeable spark issues.


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I have to agree that first pull a plug, see what is in it and how it looks. Measure the gap on it and get a pic if you can and it will give us a good starting point on where you are now. You didn't mention the heads so I assume they are stock? I am NO expert but I am putting a vortech on my 94 and I have recently gone through a lot of these questions myself.
 
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Makes sense. I’ll do that today. Thanks!
 
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Colder plug. Now that’s something I came across while researching replacement plugs.

As far as I know, the motor is stock except the SVO supercharger, which I’m told, was engineered to work with the stock heads and internals. There are upgraded fuel injectors (size unknown) and a BBK 70mm throttle body.

Given this information, what specs should I be looking for in plugs and wires?
 

ttocs

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get your 5/8" deep well out and pull the #5 plug in the front/drivers side. Its easy to access and only takes 2 mins. We can't recommend what to get until we know what you have been running and how it looks now. As long as the plug looks good there isn't a reason to reinvent the wheel just get the same plug and gap it the same. If it looks like its been running rich/lean then we need to decide what changes to make.
 
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Daryl

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get your 5/8" deep well out and pull the #5 plug in the front/drivers side. Its easy to access and only takes 2 mins. We can't recommend what to get until we know what you have been running and how it looks now. As long as the plug looks good there isn't a reason to reinvent the wheel just get the same plug and gap it the same. If it looks like its been running rich/lean then we need to decide what changes to make.
 
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Daryl

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I pulled #5 (front left, passenger side), and it is black, black, black! It’s an Autolite “Racing” # AR764, gapped at .042

I ordered and just received today a new distributor (PDI Aluminum) and PDI Screaming Demon coil. The paperwork that came with the distributor recommends their “Live Wire” plug wires which are engineered to go with a .065 gap spark plug.
 
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ttocs

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so we know your running rich we just need to figure out why. It could be the plugs, it might be the tune. When I asked around on what gap to run my plugs on my supercharger I seemed to get recomendations closer to .35. In the plug wires its important to find out if you need high or low impedance wires and i can't remember which at the moment you want.
 
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Daryl

Daryl

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so we know your running rich we just need to figure out why. It could be the plugs, it might be the tune. When I asked around on what gap to run my plugs on my supercharger I seemed to get recomendations closer to .35. In the plug wires its important to find out if you need high or low impedance wires and i can't remember which at the moment you want.
Yes, I thought even the .042 was fat. Yet the plugs/ wires engineered fir the PDI Distributor and matching coil calls for 10 mm wires(!) and a .065 gap on the plugs!!
 
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Daryl

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Here’s a thought: I sent my supercharger to Jon Bobd today for an overhaul. Maybe I’ll ask him for his take on the vest combo for my SC/75mm BBK throttle body and upgraded fuel injectors. See what, if anything, he recommends.
 
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Daryl

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* Jon Bond. Sorry, typo
 
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Daryl

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Daryl

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Little bit of oil, yes
 

01yellercobra

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Those plugs are toast. Judging by how rounded the electrode is they've been in there a while and didn't start at .042".

I'd still run the same plug and start at .035". That .065" is probably in an N/A set up.

Was it missing or anything?
 
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Daryl

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Wasn’t missing far as I could tell in the very little I’ve driven it
 
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Daryl

Daryl

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Those plugs are toast. Judging by how rounded the electrode is they've been in there a while and didn't start at .042".

I'd still run the same plug and start at .035". That .065" is probably in an N/A set up.

Was it missing or anything?
 

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