firewall holes

[62chevy302]

im trying to figure out what holes are what on this firewall. I know about the ones around the brake and clutch master cylinder. which ones are for the firewall insulation pad? I know some holes above the distributor are for wiring and I would like to move them down and hide them.

[MitchFloyd]

Heres some. I'm sure a few other guys can tell ya what the rest are for. Me I just kinda look at the pictures of originals and go from there.



Heres a decent reference pic.
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[MitchFloyd]

And in case your doing a 6cyl.
[IMG][/IMG]

[NEWFISHER]

Mitch =Floyd for the win! Nice reference

[62chevy302]

which ones are for the push pins to hold the firewall pad on?

[Brown62]

MitchFloyd, I think you have the choke wrong on the first reply... Right on the second under the master cylinder.

[MitchFloyd]

I will update and post a correct version. Thanks!

[62chevy302]

Which ones are forthe firewall pad?

[racecougar]

I realize it's a couple months late for the OP, but I made this diagram up the other day, and I thought I'd post it here for anyone who searches the topic in the future. In case of any differences, this is a '65 C10, originally equipped with the 230/3-speed column-shift.

[suxtobu65]

I think you have the "tail light wiring harness" hole and the ''throttle cable'' hole swapped..

[racecougar]

Originally Posted by suxtobu65

I think you have the "tail light wiring harness" hole and the ''throttle cable'' hole swapped..

You can see both the taillight harness and the throttle pedal arm still in place in this picture. Swapping them wouldn't be possible, as the throttle pedal arm has two smaller holes on either side of it.



EDIT: Here's a better picture.

[1963c-10]

Nice pics for reference....and still has the firewall markings....very cool

There are also differences in the earlier trucks. My 61 has the rear harness picking up under the access plate on the driver side floor board. My 63 has a rear harness that connects on the firewall over the throttle assembly.

[racecougar]

Yep, there are all sorts of old markings on this thing (and I was sure to take photos of all the markings before teardown). The truck has been in the family since it left the dealership, and it's sat in the back room of our shop for the past ~25 years, so it was very stock/untouched but also very rusty when we started tearing into it almost one year ago.

I don't know if the hole locations would have changed at all based on which factory the truck was built in, but just in case, this was a St. Louis-built truck.

[BigDan3131]

The oil pressure outlet is where my chock cable comes out on my 65 jimmy.

[cortcomp]

Old thread i know, "unused" on racecougar's truck above on mine is the reverse lights lead, which is separate from tail lights. I believe in 65 i was an option, but standard on 66.

[The Rocknrod]

I was just about to ask this question - Amazing place

[nhtc33d]

Originally Posted by racecougar

I realize it's a couple months late for the OP, but I made this diagram up the other day, and I thought I'd post it here for anyone who searches the topic in the future. In case of any differences, this is a '65 C10, originally equipped with the 230/3-speed column-shift.

Great reference!!! Thanks for for posting!!!

[BigSix]

My truck had a couple holes in the firewall...seems everybody who bought it decided to run a different CB radio wire into the engine bay. I ended up welding and I am still welding. I will be welding shut the insulation pad holes and using a stick on insulation pad. Trying to make the inside as sealed as possible which means also trying to run as much through as few holes as possible.

[Grizz1963]

What a useful posting.

I think I may have a few spare holes in my firewall.

[racecougar]

Glad to see it still getting some use!

[Ghernandez66]

Other than welding the extra holes has anyone find a way to seal them good to prevent heat or air from getting into the cab. the reason im asking its because my firewall has been painted already and never thought about the extra holes being an issue but now im ready to install new firewall insulation and would like to get all holes that im not using covered.

[LVPhotos]

Rubber plugs. Plastic ones with dab of caulking? Insulation tape, duct tape, depending on what level of cover or plug .
Lowes has metal,plastic and rubber covers in their special bin in hardware.

[Ghernandez66]

Originally Posted by LVPhotos

Rubber plugs. Plastic ones with dab of caulking? Insulation tape, duct tape, depending on what level of cover or plug .
Lowes has metal,plastic and rubber covers in their special bin in hardware.

That's what I was thinking but also was wondering where to get em. I think I got both questions answered thanks LVphotos

[patrickk1]

Originally Posted by Ghernandez66

That's what I was thinking but also was wondering where to get em. I think I got both questions answered thanks LVphotos

Usually your local mom n pop hardware stores have an amazing collection of these. I also use to buy chrome bolts for my choppers there.

[LostMy65]

Originally Posted by nhtc33d

great reference!!! Thanks for for posting!!!

x2