Under-The-Header Spark Plug Wire Routing

[JCampbell]

I’ve searched and searched and searched, and while there are multiple threads on under-the-header plug wire routing, there’s virtually zero technical information on how to accomplish this. The only commercially available under-the-header wire loom (that I’m aware of) is from Moroso (pn 72195) and it’s total garbage. Bought a set and both mounting tabs on the 2-wire holders snapped off when I tried installing them onto their respective brackets. Returned them and am now looking for another method.

I find most of the commonly used wire looms that run the plug wires over or down the side of the valve covers/heads too gaudy for me. Besides that, the CA-legal headers I have to run utilize the A.I.R. tubing which precludes routing the plug wires along the top side of the head because there’s no room to snake the wires between the head and the A.I.R. tubing. Neatly, anyway.

Aside from sourcing another commercially available wire loom kit that I’m currently unaware of, my only option appears to be fabricating my own brackets. I’d like to see what, methods have been used by any of you to route your plug wires under the headers. Looking for specific, detail-oriented responses/pics. And if you’re aware of another commercially available kit, speak on it.

Since I know it’s bound to come up, yes, I’m aware of the circle track style, zip-tie method. I’ve used it in other applications, but I’m looking for something a little more professional than that for this app.

[Jonboy]

There are 2 3/8 or 7/16 headed bolts just below the block/head flange. It seems like 80's F body cars (Camaro/Firebird) had plug wire routing that went that way, the trucks might have something similar. It may be a long shot, but an idea.

[JCampbell]

Yeah, they did, but only on the driver's side. The passenger side wires still ran over the valve covers and were held in place by a retainer that clipped to the exhaust manifold heat shield.

I have a set, and that's what I was going to do, but the parts won't easily interchange to the passenger side. For the amount of fabrication that it would take to modify the factory parts, I could build brackets out of some sheet stock that use the factory mounting bosses and use off the shelf wire retainers...which is kind of my plan, but I wanted to see how others have done it, first.

[Jonboy]

My LT1 Brougham (B body) used a similar setup, but the wires came from the front (Optispark). You could probably get a set of those and swap sides. I would think the F and Y body cars would have similar brackets, too.

[LynnJr]

A couple of tricks to do this and not burn the wires. Buy a roll of wire protective sleeve.For the tough wires that never stay were you want them, I used lashing wire. (Wire used to wrap telephone lines from pole to pole) Tape the wire to you spark plug wires with electrical or wire loom tape and then cover with protective sleeve. This way the wire stays in what ever configuration you put them in.You then use the old ramshorn exhaust brackets at the end of the block to keep everything aligned and run up to the distributor or mag.
Don't use steel separators and use 90 degree boots.Stolen from the internet.

[wraprail]

^^ Brilliant! This is what I would do! (just don't get cought stealing)

btw, Duct tape and bailing wire works best. D

[INSIDIOUS '86]

The 50's corvettes had a u shape cover that bolted underneath the manifolds. Ironically I had some on my 283 and I put them in the garbage...
Posted via Mobile Device

[Jonboy]

Vettes used that screwy wire cover through '82. The wires run under the engine mount, too.

[geezer#99]

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=156

[LynnJr]

I think there might be some confusion about my earlier post so I'll re-explain how it works.
If you don't have stainless steel lashing wire you can use welding rod.You bend the rods exactly how you want to run the wires.
On the number one plug come straight down about 2 inches then put a nice rounded bend in it.Tape the spark plug wire to the rod for its entire length under the header.
Bend the rod so it clears anything in its way.
You then put the sleeve over the wire to hide the welding rod and tape.
If your using clamp together wire separators you might need to take a dremel tool and hog out a little extra room.
This will keep the 4 wires in the correct shape so they don't touch or come to close to the header.
On the rear of the block you bolt on the rams horn style clamp to keep everything level and straight.
If your using a corrected cap distributor cap the install is extremely clean and tidy.
I think you can search the various hot boat forums for pictures as most of them use upswept dry or wet stacks and its easier to see the routing and parts.