What holes do I need in firewall?

[hpcgmc]

I've got a welder who is VERY slowly repairing the rust in my cab. I decided to remove the heater box and replace it with a vintage air heater (eventually vintage air a/c). Since I'm having the welder fill the heater box hole, I decided I'd have him fill all the unnecessary holes in the firewall.

When I got to the driver side, I couldn't recall what went where (cables, wiring, rods, etc). Here's a couple pics. Are there holes in the firewall from the factory that I should be filling? There are a few holes on the firewall above the bellhousing that don't seem to be necessary.

Any ideas?

Thanks!

[68bowtie]

this link should help. the small screw holes over the bell housing area are most likely from grounding wires or the rubber plugs that hold the sound matting on the inside.

http://67-72chevytrucks.com/vboard/s...d.php?t=233443

[hpcgmc]

Thanks for the link Bowtie- exactly what I needed! I plan to use dynamat on the cab floor, so I don't think I'll need the rubber plugs to hold the sound matting to the floor. I'll ask my welder guy to fill those holes. I can always add a grounding wire hole, if necessary.

[hpcgmc]

Hey Guys, I found a welder/body guy to weld up my rusted floor, finish up the firewall and paint the inside cab and engine compartment. I need to tell him exactly what holes to fill. All my engine stuff and under dash stuff is in boxes so I can't even pull pieces out to see how things line up for screwholes into the firewall.

See the attached pics - I've listed what I believe to be correct, based on the great link that Bowtie gave me in an earlier post, but then a bunch of unknown holes, which I've numbered. The center of the firewall I didn't bother to number, since I assume all of these holes are to hold the floor matting, so can be filled since I'm using dynamat. Can you folks identify the unknown holes and tell me what I should be welding up before painting the inside of the cab and firewall? The firewall will be skim coated for a smooth finish before painting, so I'm hoping to fill or drill as few holes as possible once it's painted. I'll be having the welder enlarge the fuse box hole for an aftermarket fuse box (apparently all the repros are made to fit the larger fuse box hole in the 68-72 firewall).

Can I fill in all the white circled holes on the passenger side, since i'm removing the heater and replacing it with a vintage air heater that just requires two hose fittings?

The truck is a 67, so the holes are a little different from the later years.

DAMMIT - all the little labels I put on the driver side holes are to small to read! I'll try again.

Also, I'm going to be using an LS engine with a fly by wire throttle, so should I fill the throttle linkage hole and the screw holes around it?

Thanks for the help!

[hpcgmc]

Lets try the driver side firewall pic again, hopefully with clearer labels.