I like to do and make anything that I can myself. So when I was looking at the tech forum posts concerning tunnel plates I saw a simple piece to make myself.
I went to my local metal supply house and ordered a piece of 3/8" Aluminium bar 48" long and 12" wide. To my benefit they screwed up and the kid in the shop cut it short. So they gave me a piece of plate instead. Plate versus bar is mostly a matter of precision. Plate is better but also more expensive.
I waited on this job until I had several things to do underneath that could be accomplished at the same time. O2 sensors, check the tranni fluid. etc.
I jacked Yvette up and got her firmly supported on jack-stands. Then I shook the car hard side to side and back and forth to be sure that she was stable. I opened the hood and removed all but one bolt on each header flange and loosened the last so that the headers could pivot out of my way underneath.
I removed the exhaust system from the cat-backs to the collector. I don't have rear O2s. As I was removing the bolts I noticed that the threaded holes are askew from the factory and so they make the holes in the tunnel plate far larger than they need to be in order to have enough slop to get the bolts in. ! So I retrieved my paint marker and sketched centerline indicators for each and every threaded hole. Then I pulled the tunnel plate out and brought it into my shop.

I laid it on top of my Aluminium plate and traced the outline with a paint marker.


Then I marked the centerline of each drill point in relation to the indicators. Then I center punched each centerline.


I set the marked plate on my drill press table and began drilling the 0.3125" holes.


I used my little precision Chamfer set to ensure that each hole is beburred the same. This is not necessary but I prefer it so there they are. You can deburr them any way that you can or want to.


The chamfered hole.


Then I move to my table-saw. That's right a regular wood oriented table-saw Mine is an old 10" Craftsman from the 50's. I putin one of my old carbide tipped blades and got a tube of lubricating wax from my work-shed. Yes wax. Mostly bee's wax but it does a great job of preventing weld-up on the carbide and it is really easy to clean off for when I do my next wood project.
Now easy does it and put wax on the blade every inch or so. If you try to cut too fast it will overheat the blade and the carbide will fly off.
If you are smart enough to *not* stand in line with the blade while cutting this procedure is pretty safe. Yeah I know some of you OSHA mentality people will argue but I didn't get hit with any pieces that did more than sting a little. But if *you* aren't carefull enough and get some injury then blame yourself and not me. I have done this same thing many times and I have *never* even drawn blood.


I used my Black and Decker belt sander with a 180 grit Silicone Carbide belt to finish the edges and deburr the plate. Being an old hand at finishing Aluminium and having a Father who was Air Force I always paint my Aluminium with Zinc Chromate. Then I covered the plate on both sides with a thermal barrier. I used a very thick coat of high temp Rustoleum Silver paint as the adhesive. Then I used the Aluminium duct tape to attach the edges. The bottom side is covered except for the bolt holes and the top is covered except where the mounting surface is.


Then I used my handy-dandy DeWalt cordless to run a 1/4"-28 tap through each and every threaded hole because I want to use some of the hundreds of Titanium 12pt Aerospace bolts that I have. I bolted the plate in place. Every hole lined up fine.


Remember you and *only* you are responsible for your actions! If you aren't competent to do this job then find a friend who is or buy the plate. Do *not* try to blame either myself nor the forum for any stupidity that *you* may accomplish.

 

I did my own myself. Definitely not a pay for mod if you have the patience for drilling those holes.

 

Addendum;
While the insulation prevents the thermal energy from penetrating the tunnel plate it appears that the heat felt in the console is from another location. I suspect that the airflow around the headers flows over the top of the plate and they heat up the frame which then transmits the energy.
So the next step is to insulate the frame near the header primary tubes.
There is plenty of thermal energy making it's way into the cabin area here in Tucson. I don't really need more.

 

WHY would you do this?

 

I made my own as well. I used a bandsaw (wood blade) to cut the plate and WD-40 as a lubricant.

The table saw idea kinda makes me cringe because of kickback, but you survived it!

 

I would have preferred a band saw but I am sadly lacking in same.
Kickback *only* occurs when one feeds the material, wood or plastic or metal, too fast.
WD-40 is *not* a lubricant! Neither for cutting nor for movement.