Any one have a neat way to cleanly get the required engine wires through the firewall while getting a good heat and fume free seal?
A good cord connector/strain relief from an electric supply house is good and squeeze tight. They come in different sizes. I use them in my SCTA/Bonneville roadster firewall.
The traditional way would be a properly-sized rubber grommet. They can be gotten various places, a good parts store with the small parts bins should have them, also better hardware stores. If you want to go modern, there are bulkhead fittings available from several manufacturers.
Not real neat, but when I first started outfitting Chief cars, I would take a very sharp taper center punch and make a hole about the same size as the wire, thread it through and put some sealer around the wire and the hole. The center punch made a real neat , smooth , hole that wouldn’t chaff the wire. Sealing the holes was important on those cars as they set around idling a lot. I also ran some wires through the floor boards at times, close to the transmission hump, the same way.... couldn’t see those when you opened the hood..... that might work for you. Bones
You want a positive, NO leak firewall connection, look into something like this... https://www.alliedelec.com/product/...VOyCtBh3gVAiXEAQYASABEgLFpvD_BwE&gclsrc=aw.ds Mike
Just as it's been already mentioned, use the correct size rubber grommet. No need to get highly technical with this. If your worried about getting fumes, you may have an issue to fix that is allowing fumes in the first place. As for heat, you can easily seal around the grommet to help with that. Still, heat from a V8 will need more than just a little sealer around the wires to keep it at bay! You would want to insulate the inside of the firewall and then some.
https://www.bluesea.com/products/category/23/Cable_Clams Marine cable clams will provide waterproof seals through a bulkhead.
I went way overboard on filling and smoothing the firewall on my '37 Chevy. I didn't want to put the wire through it. So, I bored a hole in the inner kick panel and routed the wires through there. They just disappear behind the front body mount. I used a grommet like the others have said, but I'm going to go with the next size bigger on final assembly. I will post some pictures in the next couple of days.
I once rewired a '57 Chevy using a full harness out of a "65 Biscayne. It had a bulkhead connection that broke out each section (engine, lights, charging) into three separate plugs at the firewall. I really liked the ease of figuring out where my wires were for each function. It also made it very easy to unplug (lights) the flip up fiberglass nose and lift it off the car when I wanted.
Here is my '37. The loom is from Summit and the joints are friction taped in the best Hot Rod tradition. The harness comes through the inner kick panel and is hidden by the body mount. I see in the photos that I need to turn the loom so that the seams are to the back and do a better job on the taping.
Thanx Bones, The motor mount bolt is hanging down underneath and the starter brace is awaiting a spacer
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