Thru bolt solution on shaved firewall (ideas needed)

[May70]

For those of you who have shaved firewalls. What was your solution to thru bolt connections? (please post pics)

Im looking for ideas other than maybe putting nice button heads in the firewall. I'm also worried about cranking down on fasteners over filler...

For instance the vintage air bracket has two holes where bolts enter thru the engine side - into the cab - to fasten the vintage air system.

Also the fuse block has two metal screws that come thru from the inside. Same with the steering column plate etc.

Im also going to utilize the old accelerator bracket nuts for an ls pedal bracket but dont want those bolts popping thru the firewall either.

Looking to clean it up. TY

[Jason Banks]

I did what you say you don't want to do... I just did another the same way. I was kind of disappointed that it slightly deformed the 'perfectly' flat firewall.

I swore I was going to put a stud or something on a piece of flat bar and weld that to the inside of the firewall if I had to do it again.

[May70]

Yeah, that’s exactly what I don’t want to happen

Thinking about flat bar with studs that would offset the unit about a half an inch to the rear of the cab. As tight as things under the dash seem, I would be afraid that would cause problems

[HO455]

Look at elevator bolts or hurricane hardware. Large head bolts that you could tack weld to a piece of sheetmetal and then glue the sheetmetal piece to the firewall with panel adhesive.

[LS short box]

Just a thought. Looking at the blue firewall the block off panel looks to be maybe 1/8" or 3/16" thick?
Could you counter sink the bolt holes that are for the button heads for say like 1/4" flat heads. Or if the block off plate is thin a 10-24 flare head? Weld them in with the threads going into the cab. And then grind smooth. Then body work them?
Are you running a DBW or DBC throttle? On my 68 C10 I used a DBC pedal. You can't see the pedal bolts.
Steering column wise I just ran the bolts from the outside of the fire wall to the inside.
Fuse block wise I welded up the stock hole. Then moved the Painless fuse block back from the inside of the fire wall and used "L" brackets to attach it to the kick panel. After that I made a new hole in the fire wall behind the inner fender to hide all the front chassis wiring.
I love to hide wires.
Couple of pics.

[Jason Banks]

LS Short Box, that firewall is a most 16ga or .0598 thick... not possible to countersink.

On the one I recently did, I was actually going to weld some flat bar to the inside of the firewall to reinforce. Now after thinking about it and remembering how the blue one flexed. I might cut out a plate to panel bond to the inside(it's already painted and don't want to weld). It would hopefully act like a big washer

[loudchevy]

I haven't added a VA system to my C10 yet, but I had saw someone here use/recommend this backet for trucks that had their firewalls shaved. It bolts to the floor in lieu of bolting to the firewall. Not sure how well it works but it was what I was planning on using when I did mine.

https://fullcustomfab.com/shop/ols/p...ket/v/GEN%20IV

I didn't mind the fuse block or steering column hardware in my shaved firewall on the drives side but I really don't want it showing on the passenger side with so much more open space.

[A1971Blazer]

I just used polished stainless button head screws.