53 Chevy Cab Sheetmatel Work

[jd.marshall]

I am thinking I want to go ahead and replace the firewall, floor board and rear cab panel for the following reasons.

Firewall
Engine hump has been modified and cobbled together with multiple pieces of sheet metal, angles are off and it looks rough as guts. Also has a firewall mount brake booster (I want to mount in the frame rails) with the original stamped profile ground down and very rough holes flame cut.

Floor
Overall some general rust pin holes that could be welded up and general pitting that would be covered by carpet. Of importance to me is the missing seat riser and B pillar cross brace structure. I want to go back with the original seat and seat riser structure and bench seat and it looks like it may just make sense to replace the whole floor

Rear cab panel
Both corner patch pieces were poorly welded in with a lot of distortion in the fit up and across the flat sheet metal. A third brake light was welded in and that panel has caused distortion in the rear cab panel.

The chassis is already mustang II, 350 HO turn key T350 4 link 9" balsted and painted with 4 wheel discs so i have a great foundation.

I understand this to be a lot of work and I am a rookie truck resto guy with good mechanical and decent welding skills. I also feel I might as well do this right, bite the bullet and enjoy the technical challenge. The three panlels will be well over a grand but my labor will be free. I'm kind of looking at it as a buy once, cry once deal on a nice (not show class) back country driver.
I think that I will need to install temporary cross bracing for removing and replacing these three sections at a minimum.

I would appreciate your all thoughts and comments on this and I am also curious on the best order of operations to replace these three major sheetmetal sections. Which panel (floor, firewall, rear cab) first, second and third?
Also would appreciate reference to any build posts with good examples.

[dwcsr]

As long as you brace the cab properly you should do ok. Anyway you go about it its going to be a bear to get fitted. You will need to find a way to support the cab when the floor is out.

Adjust the doors so they look good, if the hinges are shot fix them first, every thing will be done with the doors on so you can check the fit as you go. Once all is permanently tacked in place you can take them off.

Brace across the inside of the doors front to back about midway up to keep the pillars in the same location, measure the door opening as it is now and write it down. You want to be able to close the doors with the braces in-place. You can do a brace side to side if its really a shaky cab.

Replace the firewall first it gives you another solid panel to mate the new floor to and gives a fixed point of location to use in the front.

Then pull the back off and then remove the floor, clean up and repair anything that needs it and then slide in the floor leaving it un-welded and not tacked but clamped to the firewall lower lip, This is your location point in the front for the floor height, it should also drop you in the correct place for the front pillars,

Now put the back panel on, get it lined up with the door belt line and make sure the door gaps are good and the seam is closed and heavy tack or sheet metal screw it in to place on the door jams.

Jack up or down the floor to meet the points at the rear spot weld edge under the window, clamp it and move on to the pillars.

With the door closed the door bottom should be even with the rocker with an even gap front to back

Once the pillars are looking good and the doors look like they belong on the truck and open and close nicely start welding the floor to the pillars then move on to the front edge and the rear edges and around the corners and up the pillar.

.

[mr48chev]

I had to look at that firewall three times before I figured out that mess goes out into the engine compartment. My question is "why. Yep I'd change that.

The rest is up to you as far as time and money goes. It's your time and your money.

I'd think getting the doors fitted correctly with good gaps, and then bracing the cab before removing major sections may be prudent in the long run. Just as making sure that it is sitting square and level either on or off the frame before doing major body work is. You will never be upset with yourself for going overkill on the bracing or prep work before doing the changes but if you don't and it doesn't go as well as it could have because of that you will be kicking yourself around the block long after.

[jd.marshall]

Thanks for the input guys and Dave especially all the pointers on sequence. Looks like I need to sit this thing on the frame and get these doors right and brace the hell out of it.

PM back to ya Dave

[dwcsr]

I would do most all of it off frame except the firewall. If you have a 5 window you can hang this up and have the bottom completely open to work on it. Use the hood hinge bolt holes and make a plate for it then weld some legs on it for the front. You can pass a 4x4 through the corner windows and make some type of support for it keeping the original floor level front to back and side to side. What your attempting is a big project and you need room to get in and under it. The bracing will keep it in place while it hung up in the air.

[MARTINSR]

I have never understood for the life of me why the firewall needs to be recessed on these trucks when they had an inline six in them from the factory! An engine 8" longer than the SBC fit in them but somehow the fire needs to be recessed when a SBC is installed? HUH?

Brian

[hotrod1]

the further you can get the engine back, the better for weight distribution. Trucks are front heavy and back light. The closer you can get to the 50/50 (front/back) weight distribution, the better. If you could care less about handling, the firewall can stay the same unless there is a clearance issue.

[MARTINSR]

Originally Posted by hotrod1

the further you can get the engine back, the better for weight distribution. Trucks are front heavy and back light. The closer you can get to the 50/50 (front/back) weight distribution, the better. If you could care less about handling, the firewall can stay the same unless there is a clearance issue.

I don't honestly think moving the motor back eight inches on such a big vehicle with such odd weight distribution to begin with is going to do jack.

Proper changes to the suspension would do a lot more. I mean think about it, on a 2010 Chevy pickup the engine is WAY over the front axle center point.

I moved my motor back a little more. This was back in '79, yes that's the oil pan you see under the cab, this truck is drivable in this photo.



It handled like CRAP, and it had almost perfect 50-50 (maybe even perfect) but the suspension is much more important to which I did nothing.

Brian

[dwcsr]

Originally Posted by MARTINSR

I have never understood for the life of me why the firewall needs to be recessed on these trucks when they had an inline six in them from the factory! An engine 8" longer than the SBC fit in them but somehow the fire needs to be recessed when a SBC is installed? HUH?

Brian

I think it boils down to what clip you end up with and what fan you use, are you using aftermarket mounts. I have seen many SBC's installed with no recess. The only thing they did was beat the fire wall where the Distributor is.

The factory V8 truck had a different firewall, It's a subtle difference and I only noticed it when I had a 6 cab next to an 8 cab. The firewall is deeper at the distributor and shaped a little differently.

Length of the engine isn't a factor, its where the bell housing sits at the cab and that's usually determined by the rear bell mount and cross member unless its removed or moved.

[MARTINSR]

Originally Posted by dwcsr

I think it boils down to what clip you end up with and what fan you use, are you using aftermarket mounts. I have seen many SBC's installed with no recess. The only thing they did was beat the fire wall where the Distributor is.

The factory V8 truck had a different firewall, It's a subtle difference and I only noticed it when I had a 6 cab next to an 8 cab. The firewall is deeper at the distributor and shaped a little differently.

Length of the engine isn't a factor, its where the bell housing sits at the cab and that's usually determined by the rear bell mount and cross member unless its removed or moved.

I don't know, I have only did one SBC swap and it required ZERO mods to the firewall. I raised up the floor right at the base of the firewall, that was it so the bell housing could clear. But the distributor, plenty of room.

Brian

[dwcsr]

Originally Posted by MARTINSR

I don't know, I have only did one SBC swap and it required ZERO mods to the firewall. I raised up the floor right at the base of the firewall, that was it so the bell housing could clear. But the distributor, plenty of room.

Brian

Sorry I had a brain fart I was thinking of a 55-59, they a different firewall for a v8. But again if you use a stock rear mount and a 55-60 v8 bell you'll have a clearance issue

[jd.marshall]

How hard should I work on door alignment before bracing? My doors have new hinges and I haven't done a lot with them except take one off the cab to start some cowl work. How hard should I work on door gaps at this stage? I would think a mock up and brief adjust to make sure nothing is way out then brace up the cab solid pull the doors and get to work.

[dwcsr]

Originally Posted by jd.marshall

How hard should I work on door alignment before bracing? My doors have new hinges and I haven't done a lot with them except take one off the cab to start some cowl work. How hard should I work on door gaps at this stage? I would think a mock up and brief adjust to make sure nothing is way out then brace up the cab solid pull the doors and get to work.

Its not necessarily how good they are but rather are they close and workable. You want to have the same gaps when your done so the better it looks now the better and easier it is at the end. Get it where you think its OK and take a few good pictures for reference later.

the best way I've found to adjust doors is loosen the bolts and close the door. move it to where you think it looks good and have a second person inside to tighten up the bolts. It will get it close enough to start bracing.