When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I’ll be installing the new MSD plug wires and Billet Specialties wire looms over the next couple of days.
I purchased a set of the plug wire boot protectors (insulators) to protect the wires and boots from the header heat.
I’ve never used them in any other build and I’ve never melted a single boot or wire.
I have about 1/2” to 3/4” spacing between the boots and the primary header tubes on all cylinders and I’m wondering if they are really necessary, or are they just a new marketing tool for us to spend money on.
I do think they are really ugly and would rather not run them.
This is not my engine but it does show the wire looms I’m installing and the spacing I have between the header primary tubes and the plug wire boots.
Last edited by OldCarBum; Apr 5, 2026 at 10:54 PM.
Been running MSD wires for 25+ years without any spark plug boots melting. I use the 90 degree spark plug ends as my heads are angle plugs. Those straight ends won't work on my engine.
Been running MSD wires for 25+ years without any spark plug boots melting. I use the 90 degree spark plug ends as my heads are angle plugs. Those straight ends won't work on my engine.
Thanks!
I’ve had the same experience over decades of car projects and never had a melted wire or boot.
I’m wondering if the plug wire manufacturers are using poorer quality products than they used to causing the boots or wires to melt at a lower temperature or if this is just some gimmick to get us to spend more money for something we don’t actually need?
I’ve had the same experience over decades of car projects and never had a melted wire or boot.
I’m wondering if the plug wire manufacturers are using poorer quality products than they used to causing the boots or wires to melt at a lower temperature or if this is just some gimmick to get us to spend more money for something we don’t actually need?
With all the junk sold today it wouldn't surprise me on the quality drop. I replaced all my wires when I switch over to EFI just because my old wires were coming up on 15 years old. It was time. I put the same MSD wires on (cut to fit kit) and they are surviving fine so far.
Every time this comes up, I suggest ceramic plug boot wires but all you ever get is "crickets" after that. It's like people are afraid of them or something. I have them and they work great. Those plug sox are pretty ugly.
Every time this comes up, I suggest ceramic plug boot wires but all you ever get is "crickets" after that. It's like people are afraid of them or something. I have them and they work great. Those plug sox are pretty ugly.
No crickets here I've just never had an issue. If I did I would probably go with those.
So this morning I called MSD and asked what they recommend and this was their response.
If you are running an engine that puts out an extreme amount of horsepower (1000+) that runs extremely hot, under race type conditions with race fuel or nitrous, then they suggest running the protectors.
If you have plug wires or boots that are either touching or are extremely close to the header tubes then install the protector.
If you have over 1/4” clearance between the header tube and the wire or boot, not running extreme horsepower or fuel additives on a street driven car, then they see no reason to install the protectors.
They concluded that every engine and situation is different and they said to run the engine under my normal driving conditions and if I see any issues then add the protectors.
So for now I’ll leave them on the shelf and see what the future holds.
Thanks guys!
So this morning I called MSD and asked what they recommend and this was their response.
If you are running an engine that puts out an extreme amount of horsepower (1000+) that runs extremely hot, under race type conditions with race fuel or nitrous, then they suggest running the protectors.
If you have plug wires or boots that are either touching or are extremely close to the header tubes then install the protector.
If you have over 1/4” clearance between the header tube and the wire or boot, not running extreme horsepower or fuel additives on a street driven car, then they see no reason to install the protectors.
They concluded that every engine and situation is different and they said to run the engine under my normal driving conditions and if I see any issues then add the protectors.
So for now I’ll leave them on the shelf and see what the future holds.
Thanks guys!
What the heck are crickets???
Good common sense answers. Thanks
I forgot to mention my headers are Jet-Hot ceramic coated inside and out.
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 C4 of the Year Finalist - Unmodified
2025 C8 Stingray of the Year Finalist - Unmodified
I use the protectors on my big blocks that have headers. Some of the wires do touch the headers. I don't really like the look but don't want to take the chance of burned wires.
Using L88 compression I find that my ceramic coated long tube headers CAN burn those MSD "superconductor" wire's spark plug caps if it touches or is close to the header tube. I have used those ugly spark plug boot's ever since.
Just be careful as those spark plug boots will smoke and stink while they break in. The best solution was to put on a good set of wire separators and then the wires are not touching the headers..
With all the fancy stark plug boots out there I found that the simple 90* was the best for 6-7 cylinders out of the 8 on my engine. The next time I build a new set of spark plug wires I might put the stainless wire sheathing to protect from getting or releasing any electrical noise.
Last edited by ctmccloskey; Apr 7, 2026 at 04:14 PM.
Thanks everyone.
I had my headers ceramic coated inside and outside for better heat reduction.
The plug wires are the MSD multi angle type so that once installed they can be bent to provide additional clearance.
I am using the Billet Specialties wire looms in the pictures in post #1 (not my engine) to help keep the wires in place.
I would consider the OEM sparkplug insulators from an LS-3,7 or 9. They are spring loaded aluminum barrels that surround the boot. And they don't look bad either, in my opinion.
With the loams and the flexible ends, you'll probably have plenty of clearance.
Are the fabric boots any better to your eye? I run something like these in my 80 with headers (which I must have bought on eBay, so here's a link for what I bought for my LS6). All sorts of colors, just read the reviews to make sure they clear the plug ends you are using.
With the loams and the flexible ends, you'll probably have plenty of clearance.
Are the fabric boots any better to your eye? I run something like these in my 80 with headers (which I must have bought on eBay, so here's a link for what I bought for my LS6). All sorts of colors, just read the reviews to make sure they clear the plug ends you are using. Spark Plug Wire Boots (Amazon link).
Those are basically the same ones I bought, from Summit but mine are black.
Today I received the new ARP 12 point bolts for the looms.
I installed those and torqued the plugs into the heads.
I was surprised that Edelbrock’s instructions state to lubricate the plug threads and only torque them to a maximum of 10 ft pounds.
Spark Plug Wire Boot Protectors???
I have them and they work great. Those plug sox are pretty ugly.
