firewall relocating

[whitedog76]

I know there's plenty of set back firewalls out there.

But, has anyone moved the firewall or extended the toeboard for more leg room?

[whitedog76]

Here's what I'm thinking...

Leave the cowl to firewall area alone so there is no issue with hood fender, or door alignment.

The kick panel would need to be extended. Drill a hole further back for the floorboard mount.

The toeboard area would get smaller, but the firewall would get longer/taller.

The inner fenders would need to get shortened also.

These pictures are of a Direct Sheet Metal floor install, for reference. Tell me if I'm missing something.

[Erics51chevy]

I dont see a problem with more leg room. Good amount of work but would be worth it.

[whitedog76]

My floors, toe board, kick panel etc... need replaced anyhow. So, I was thumbing through the assembly manual and looking at others firewall and floorboard installs. Just got me thinking.

I'm no sheet metal worker, but I can run a grinder and welder.

I know others have installed different seats, steering wheels, even extended the cab.

I just went on a 500 mile trip in my 09 truck. Being able to stretch your legs out is great. So, I've been running back and forth with a tape measure to see what could be done.

I have a 6 cylinder, not a V8 installed, so I don't have some of the clearance issues as others may have.

[dsraven]

with a 6 banger you may be able to pull it off if the plan is a firewall mounted brake booster and pedal set up and also a different than stock steering gear set up. otherwise those items may just be right in the middle of your free foot space anyway.
before you start I would say brace the cab, with the doors hung and adjusted fairly close to good, so everything stays in the shape it should be. do bracing in an X pattern, side to side across the dash area and fore to aft in the door openings. after that the doors could be removed for ease of access. keep in mind you will need to try to leave yourself some room to work with the bracing installed. when I braced my 57 cab I used some 3/4 black pipe because it is cheap. I installed a horizontal cross bar from side to side just high enough off the floor so a 4x4 would fit under it through the door openings. that made it easy to lift the cab by myself with a couple of long 4x4's and some saw horses. then used some X pattern braces from above there to each upper and lower corner. that held things solid. remember though, that you will want to check the seating position with your new firewall so try to leave foot room access if possible. then cut away the firewall only. mock up what you want to do with some heavy cardboard and duct tape and see if you like it and if it will fit around the engine and trans and still leave you foot room around the pedals. try to keep the seats and that part of the floor intact so you can sit in the cab with the firewall cut out. if it works then it's great. if it doesn't work then you planned on doing the firewall anyway. the floor wasn't cut out yet so that part wasn't affected.

[whitedog76]

I actually saw a build done where they made boxes in the toeboard. It was on a Brit. site, which I can’t find anymore.

Anyhow, my way of thinking is to do the firewall mod first. Brace it between between the hood hinge brackets to help keep the cowl in place. I have 2 1/2 inches before the firewall recess gets into the motor. Ideally I would like to move it 3”, so I’ll have to decide on that. Maybe a setback recess or just go 2” and modify the toe board.

After the “new” firewall is tacked in place, then Start in the cowl, toeboard and floorboard. My doors shut good and the frames are in decent shape, so only doing one side at a time seems to be the smart way to go. That way I always have a reference for measuring.

This is all theory right now, I have an MII to install, an 8.8 to get underneath, and about 5000 other things I can’t think of right now. The floor of these trucks are tapered too, not to mention the curve in the kick panel pieces, so it won’t be an easy undertaking anyhow. I’d like to do it I need a way so if things go south, I can always go back and fix things.

[Erics51chevy]

Go cut the floor where your feet are and weld in a bigger peice. If something else gets in the way later, cut that and reweld it. So on and so forth. Just dont get in the way of the wheels.

[whitedog76]

Been driving this one since 2005. Kind of part of the family. I've had it longer than my kids.

The first cut with a sawzall will be a hard one. Kind of like putting down the family dog.

Also, here's what my plans are for the drivetrain.

[Erics51chevy]

Took the engine and trans out of my dad 01 chevy work truck. We worked together in it since he had it. He was also upset to see it go. But i gave the heart (engine) a new home.

[whitedog76]

After going through this site. Found this 55 going under the knife for a TB firewall.

I'm beginning to change my mind on my original plans.

[Scott2]

Sounds interesting! I am in the final stages of assembly on my '51 and there is already not much room in that area. The steering, exhaust, auto shifter from my column, brake lines, an added park brake cable (or perhaps the stock setup), the inner fender is very close there as you noted, etc. Also have oil and water temp sensor wires, the O2 sensor wire, the oil filter is snug up in there, maybe a throttle cable if you have one, - lots of things will get affected and crowded! The idea is tempting but be sure to mock things up as much as possible before you get too far.

The other thought is that moving the floor doesn't help with the distance to the steering wheel. I moved my tank under the bed, pushed the Flaming River column as far forward as possible and I'm looking for a flat dish 15" wheel, and swapped for a 1990-ish bench seat which has a much thinner back that allowed me to push it and me to the rear of the cab. Still tight but better.

Good luck! I want to see how this comes out.

[dsraven]

https://67-72chevytrucks.com/vboard/...d.php?t=348244

found it. a 52 burb onto an envoy. bbeep is the thread op. a few pages with lots of pics if I remember correctly. maybe get some ideas.

[b-mac]

Finally a perk of being short!!

I would hit my exhaust manifold quickly, but that is a solvable problem too.

Mock up a cardboard box on the engine side that will clear everything. Get it perfect. Replicate out of 16 gauge. Cut out existing firewall/toeboard. Weld in box. Seems like it would work easy enough. I did the opposite when recessing for the heads into the firewall.

[dsraven]

somewhere on here a guy did a panel from your vintage and placed it on top of an envoy floor and frame. turned out nice too. just cant remember the post name.

[Erics51chevy]

Have fun! Its only metal!

[whitedog76]

from a grand scheme of things, it's pretty much all going to have to come out on the 54. So I really don't have much to lose. Most of my hair is gone already anyway... Anyhow, I'm believe I'll have to use lots of bracing and find some strong friends to help out.

Figuring out how to go about chopping the TB is another issue. I guess 1, piece, 1 pile at a time.

I've been going through BBeep's thread, even saved a bunch of his pics. I've seen some other threads& forums that have done similar builds. In fact the pictures I posted earlier were from an SSR grafted into an AD truck.

[dsraven]

you can see in post 8 the pics shows the envoy floor inside the 57 gmc cab.it is too narrow as you see by the envoy kick panels on each side. the nice thing is you get a trans hump, a console shifter=cable operated and set up for 4l60E,a console if desired,a firewall with mounted brake booster and a single pedal for automatic vehicles, and a mount for a gas pedal for drive by wire.there is a nice round grommetted hole for wiring to pass through on the firewall and a steering column hole as well,however it may be low. use the steering column as well if possible.if you use the floor as well you could also use the seats which come with integrated shoulder belts. measure up what you need and keep in mind that the envoy has the trans hump offset to the pass side a bit. don't just cut the same amount off each side and expect it to be centered.

[whitedog76]

Originally Posted by dsraven

you can see in post 8 the pics shows the envoy floor inside the 57 gmc cab.it is too narrow as you see by the envoy kick panels on each side. the nice thing is you get a trans hump, a console shifter=cable operated and set up for 4l60E,a console if desired,a firewall with mounted brake booster and a single pedal for automatic vehicles, and a mount for a gas pedal for drive by wire.there is a nice round grommetted hole for wiring to pass through on the firewall and a steering column hole as well,however it may be low. use the steering column as well if possible.if you use the floor as well you could also use the seats which come with integrated shoulder belts. measure up what you need and keep in mind that the envoy has the trans hump offset to the pass side a bit. don't just cut the same amount off each side and expect it to be centered.

It's a good thing I have an AD truck. How much narrower is the cab do you think? My initial thought process is to leave a flange around the floor of the cab and sit on top, then see where it leads. I already have the 4200 mocked up slightly to the passenger side to begin with. As far as seats, I kind of like the bench seat though. As long as the tunnel will clear the frame bracket, it may stay that way.

[R&B51]

I remembered this build. Nice the way this guy (Australian?) details his build and good ideas. He even appears to market an AD hardcover bed cover he designed?
Anyway, here’s a link to what he calls “podding” the firewall and I saved it in my mind since I’m working on a 51 and am 6’2”.

http://www.1952chevytruck.com/1952ch....htm#stripdown

[Erics51chevy]

I was thinking about this whole thing yesterday (instead of focusing on work ) and if your going to move all the pedals back, my f350 and expedition have a switch on the dash for electric pedals that move them closer and away from you. Maybe a trip to the junkyard? Thinking outloud for a shorter person driving it.

[whitedog76]

Pedal location isn't really the issue. I was thinking more on the lines of being able to stretch my legs out when rolling with the cruise control on.

The electric pedal is kind of a neat idea. I think the Trailblazer and Envoys might have had that option on the higher end ones....