Lessons I have learned on swapping cabs onto my 63.

[Tx Firefighter]

I posted two days ago about the 62 cab I got to put onto my 63 truck project. That post is HERE

A couple of things came up that I thought I would warn you folks about when doing this swap...

First, the 60-62 cabs have the hydraulic clutch, my 63 uses the mechanical linkage type. You must bore a large hole in the floorboard for the mechanical rod to pass through, as the 60-62 cabs don't have it. Also, the dual master cylinder/ clutch cylinder unit has a funny cutout in the firewall that you will need to weld up and redrill for the later type of master cylinder. No big deal overall, but you better plan on a few hours work to do these mods.

Second, the front mounts on the 60-62 cab are no where near fitting the 63 frame. You have to relocate the holes for the front mount holes inboard about 6 inches per side to get the bolts in the proper place. You could build a new frame mount to line up with the old cab, but it's much easier to modify the cab instead of the frame.

I will get pictures and exact measurements tomorrow when I get home from work. None of this stuff is too big a deal to overcome, I just wanted to let everyone know that these cabs are no where near directly interchangeable.

[lolife99]

Good info.

[jonzcustomshop]

It would be great to get the cab mount pics, people ask about this kind of conversion all the time.

the steering column will be different too. the 60-62has a rag joint up by the cab,and onr at the box, the 63 -only at the box. the turn signal stuff is all diffefent as well.

[Tx Firefighter]

I will get the pics tomorrow of the cab mounts.

I won't be able to offer anything about the steering column though. I am going to be running a 72 model tilt column and intermediate shaft down to a later model steering box.

[63sbssbbw]

I too am doing this conversion,'61 cab on a '63 chassis
I'm pretty sure that if you're replacing floorpans and cab mounts(as I am) they're made for 63-66 any way
If not you'll have to move the divot, cup washer(?)and sleeve inward to match up with the frame mount.
T

[1962k20]

Im getting ready to put a 60 c-10 on a 62 k-20 frame myself. I noticed a few changes. The heater delete plates diffrent, several small changes I noticed studding the both cabs.

[aerotruk63]

This is good information for the This I know Thread.

[Tx Firefighter]

All right fellas, here is the update with pictures as promised.

The description offered by 63sbssbbw is right on the money and well stated. The rear cab mounts are the same. They bolt straight up with one difference, the 63 cab used a 1/2 x 5 inch bolt. The 62 cab uses a 7/16 x 5 inch bolt. Mounts are the same, just one size skinnier on the bolt itself.

The front mounts are where the difference lies...

Drop the mount bolt through the floorboard...


Climb underneath and here is what you will see...


My floorpans aren't quite rusty enough that I am going to change them. I just plan on cleaning them, etching them, and POR15 them. So, I will re-drill the mount holes inboard as needed to line up with the frame mounts of the 63 frame. It also looks like I will have to build a shim about 3/8 inch thick to space the front of the cab up to level the nose of the cab.

The second part of the deal, which I haven't exactly decided which route to take is the master cylinder. The 63 cab used a normal master cylinder bolt pattern with two horizontal bolts...


The 62 cab has the dual hole deal, and does not allow a later model 2 bolt master cylinder to bolt on.


I think I will wind up shaving this part of the firewall smooth, then installing the underdash brace out of the 63 and drill the needed holes in the now shaved firewall. This will allow me to run a later model disc brake master cylinder.

[jakelyons]

I very interested in how this works out. Debating trying to add a dual master cylinder mod with a booster in the 63 (Want to upgrade the brakes mainly because I'm rebuilding this truck for my daughter.)

Might have to take a drive sometime to check out your truck. Before I start reworking my suspension. Thanks for the offer.

[Tx Firefighter]

Come on with it. I am happy to show you any and everything I have learned. Bring your camera too.

[mr48chev]

Sometimes what looks like it will be so easy to do isn't easy at all.
Looks like you have a handle on it though.

[63sbssbbw]

Looking good Kevin
Take notice of the 2 layers of sheetmetal and rolled edges aruond the MC hole (for rigidity I'm sure).
My plan is to cut/swap the whole section (out to where it's single layer) from a '64 cab,then just go the regular PB route that everyones doing.
Trent

[MacAttack]

Excellent information, Kevin.

Mac.

[forestb]

In that photo of underneath the cab is it bolted together or just resting on the mount? If so how is it drilled? or if not how are you going to drill it and reinforce it?

[Tx Firefighter]

Originally Posted by forestb

In that photo of underneath the cab is it bolted together or just resting on the mount? If so how is it drilled? or if not how are you going to drill it and reinforce it?

Right now it is just sitting there. I figured I'd drill it up through the bottom so the drill bit would pop through the pan in the right place. I'm not sure about reinforcement yet. Probably weld a sleeve inside of the cab support to take the crushing force from tightening the bolt.

[ChiefRocka]

Why not run hydro instead of mechanical on the linkage ? Mabey run an aftemarket master and slave ?

[Tx Firefighter]

Originally Posted by ChiefRocka

Why not run hydro instead of mechanical on the linkage ? Mabey run an aftemarket master and slave ?

I've already spent a lot of effort detailing and powdercoating my transmission and bell housing. Plus, I have all new GM clutch linkage from the front to back, everything (my buddy is a GM parts man). I don't want to fuss with getting another older bellhousing and buying the hydraulic stuff.

[Tx Firefighter]

A little update: I got the firewall shaved of all unneeded holes and converted to a later type of master cylinder. This description won't likely make sense to anyone but 63sbssbbw.

The early dual unit master cylinder has a funny bolt pattern and does not allow converting to a later model disc brake master cylinder like I need. The early master cylinders use diagonal holes and the later use horizontal holes.

The way around this is to weld up the extra hole in the firewall where the clutch pushrod passes through. Then, under the dash, remove the brake pedal bracket and replace it with a 63 and later one. Then, you can drill the holes through the firewall for the later master cylinder and bolt it into place. This allows the master cylinder bolts to thread into the underdash brace as factory and gives full strength of the double wall firewall.

This is the before pic...


Here is after shaving the extra holes and painting the firewall...


I still need to get under the dash and drill through the brace to make the holes though the firewall to bolt the later master cylinder on. The paint is still fresh, so I am going to let it harden a day or two first.