What are these holes for?

[muddpile]

Like the topic says, I have no idea what some of the holes in the firewall are for, and I'm getting into bodywork now, so I'm welding any unused holes shut. I know some are for insulation rubber retainers, and I want to get rid of those, but others I'm not sure. Anything with a ? beside it is what I need.

In this one, I think the bottom left one is a firewall insulator retainer hole, and the top right is for one of the heater box mounting bolts, but I can't remember.



I think the two on the left are for insulator plugs again, but the center one has me lost (it looks very crude, and may not be original). The top left three I think were for the window washer, and maybe some wiring??? I am running a painless harness, so will I need these? Also, is there a better way to route the hoses than the stock way?



When I got the truck, the hole you see on the bottom to the right of the column was just like that, with a nut welded inside the truck and only a bolt threaded into it. What was it ever used for? I realize the two above the fuse block are for wiring, but again, will they be needed with the painless kit? Thanks!

[jugernot]

I save this from another thread.

[GREASEMONKEY72]

in the second to last pic i believe one of those holes were for the ground straps that went to the valve cover bolts

[John Fabris]

The hole in the center of the curved firewall is the hole from the interior screw that holds the heater vent.

[muddpile]

Thanks guys! Looks like I can weld up the oil pressure hole for sure. I'm looking at old pics from before I disassembled, but the thing was so filthy and incomplete, that its hard to tell where anything went