47-55.1 Stretching the cab

[mr48chev]

I'm not a fan of most chassis swaps just for the sake of doing a chassis swap but it helps a lot if one is very familar with that particular chassis.

Looking back though this thread, that blue panel turned into 4 door with 4 streetched doors is high level body modifying simply because it sneaks past the unknowing eye as appearing to have been that way from the get go. The just right length quarter windows in DS Raven's truck that look like it should have left the factory that way. I was going to do that on my stretch cab and even drug a rusty old suburban home from Roslyn Wa to use for window surround parts but decided that I didn't like the quarter windows on an AD all that well after seeing some. Right now I need something for a shop to work in and am to the point of trying to find a suitable shipping container.

[dsraven]

thanks for the kind words mr48, appreciated.

how much room do you have for a shop? is there a budget?
possibly a shipping container with an add onto one side to create a wider work space? 2 containers placed side by side with the sides cut to make a wider shop space to work in? 2 containers placed side by side with a roofed space between them for a shop and using the containers for storage? possibly a commercial tent type structure? a home depot garage package? a pole type structure, like a barn, with sheeted sides? are there any backyard lumber mills near you that make affordable rough finished timbers? maybe a building mover that has something in their list of things that would work with some modification? a neighbour with an empty building to rent for cheap? a demolision company with cheap building materials, like good used trusses, etc?
I think just a shipping container would be too narrow to do any work in, unless you are just working on pieces of a project and not the whole vehicle inside. they may be a little short if you are wanting to work under something or havea project sitting on blocks etc.
thoughts?

[dsraven]

I bought my envoy at an isurance write off place. it had scrubbed something along one side, not hard, but the adjuster wrote it off probably cuz of prices to replace the panels, glass etc
finn, just as a side note, if I was to do an extended cab again i would make the doors longer instead of addinga side window behind the door. it would be much easier on an AD truck because the door skins are flatter and there is not the tapered body shape built in l;ike a TF truck has. just my thoughts though.
how does an AD shape up to fit onto a TF frame? would you use the stock suspension? isn't the TF a wider truck, generally?
you might find some body dimensions for both on the old car manuals project site

[FinnDiesel]

dsraven, I haven't looked into the measurement particulars yet, but really like how robust the TF frame is. It's just initial thoughts at this point. The frame I have is absolutely mint perfect. The Northwest Territories is sure easy on rust over the years. It still has factory paint on it and no broken bolts while taking it apart.
Yes for sure modern suspension bits - leaning towards Aero/SS axle stuff - we'll see, as I usually have a need for 4WD.
The cab room is my problem, no leg room, no room to recline and nowhere to put your stuff. Have you seen measurements anywhere between the AD and TF cab for leg room? Hard to find info. I'm used to being snug in my old Esprit, but I can still stretch my legs out straight and it has a trunk behind the engine.

[dsraven]

I think that site will give basic overall dimensions from different manuals.
Another site, for a TF factory assembly manual, would be yhe tfifive site. Just Google Chevrolet truck factory assembly manual and choose that site. Free download

[mr48chev]

Originally Posted by dsraven

how does an AD shape up to fit onto a TF frame? would you use the stock suspension? isn't the TF a wider truck, generally?
you might find some body dimensions for both on the old car manuals project site

The primary width differences are all in front of the front cab mounts. TF is pretty well square front to rear while AD is tapered from the front to the rear except under the cab it's self. 3/4 ton AD are square from the front cab mounts back.

AD front axle spring bolt center to center is 26-13/16 While TF is 31.88. That is five inches wider at the axle.

[leegreen]

AD cab interior


90s CK series truck interior


AD / CK regular cab
legroom 41.75 / 41.81 (at max rear seat position)
height of front of seat 14.25 / 16
height of bottom of wheel 21 / 22.4
Angle of backrest 8 / 8
distance from backrest to bottom of wheel 13.5 / 17
wheel diameter 18 / 15.25
headroom 37 / 34

There is not that much difference! Especially if you ditch the 18" steering wheel.

Before mounting seats, column or pedals I sat in all the cars and trucks I had easy access to, adjusted things and measured, then laid it all out on a full size side view of the AD cab on shop floor, worked out where to mount things from that. Once you get 4 or more measurements marked all within a inch or two of each other, the answers become pretty obvious and look remarkably like the pictures above

[dsraven]

this site has some good specs on newer trucks if somebody is interested in dimensions etc.

https://www.gmupfitter.com/light-dut...prior-to-2013/

[dsraven]

ok, don't know why that last post showed up twice. the site security thing can be frustrating but we gotta work with it I guess.
anyway, that site shows seat angles and dimensiions as well so might be a good site for those looking for a donor seat, or for frame dimensions, etc.

[leegreen]

A point I meant to make about extending the foot well forward: As shown in the dimension I posted, it would only going to help those with longer than normal legs. People that would feel a lack of legroom in most regular cab trucks regardless of age.

lengthening the cab does give more arm room and a seat that would recline

[FinnDiesel]

Originally Posted by dsraven

ok, don't know why that last post showed up twice. the site security thing can be frustrating but we gotta work with it I guess.
anyway, that site shows seat angles and dimensiions as well so might be a good site for those looking for a donor seat, or for frame dimensions, etc.

It's to get your posting numbers higher!

[FinnDiesel]

Originally Posted by dsraven

this site has some good specs on newer trucks if somebody is interested in dimensions etc.

https://www.gmupfitter.com/light-dut...prior-to-2013/

Their site seems to be experiencing some difficulties today . . .

[FinnDiesel]

Originally Posted by leegreen

AD cab interior
Attachment 2434769

90s CK series truck interior
Attachment 2434770

AD / CK regular cab
legroom 41.75 / 41.81 (at max rear seat position)
height of front of seat 14.25 / 16
height of bottom of wheel 21 / 22.4
Angle of backrest 8 / 8
distance from backrest to bottom of wheel 13.5 / 17
wheel diameter 18 / 15.25
headroom 37 / 34

There is not that much difference! Especially if you ditch the 18" steering wheel.

That's nuts! 41.81" vs 41.75" for leg room. No difference in 50 years. I just remember all the square bodies I drove 30 years ago always gave me calf cramps which I could not get rid of while driving.

[dsraven]

I extended my cab so i could fit a regular set of high back buckets in there. i'm kinda tall at 5' 8 1/2 (lol) but I still like my seat back a wayz. dunno how the REALLY tall guys fit in the old trucks.

[mr48chev]

As per the images that leegreen posted actual leg room is within a few frog hairs between AD and the 90s CK standard cabs. The big thing I see is that the well fed guys complain about space under and behind the steering wheel and at 290 lbs I am in that brigade but put in a smaller wheel a long time ago.

With my plans to chop and section my 48 I knew I needed extra length in the cab and my buddy just happened to have a GMC 1/2 ton long bed frame that he gave me after he put a custom frame under the cab that that frame came from for a guy. 9-1/4 extra stretch in the cab and the short bed stays it's orignal length. Then I mess with minds when the nit pickers look under the back and it has a 1/2 ton frame rather than a 3/4 ton frame.

[70chev383]

I went a little over board and went with stretching the fire wall. Wasn’t to bad as I had the hole floor cut out anyway. 3 inches at the top and about 11 inches at the floor, I’m 6ft 3 and can sit with very comfortable

[dsraven]

great idea. and ribs for added rigidty will help. possibly a few weld on braces from the underside as well? should be easy to install soundproofing and flooring material too, since it is flat with square corners

[leegreen]

Nice, Can you show more pictures of the cowl area inside and outside to show how you transitioned from 3" to 11"?
Are you planning to move the wheel & seat location/angle?

[70chev383]

Originally Posted by leegreen

Nice, Can you show more pictures of the cowl area inside and outside to show how you transitioned from 3" to 11"?
Are you planning to move the wheel & seat location/angle?

I pushed the firewall up and spread apart as well to use the original shape of the fire wall, haven’t finished bracing the back side and the tunnels not done
Don’t have a great picture of the bottom, cab mounts bolts are in orginal’ish location

Have some thin back bucket seats out of a Suzuki suv, I also have tilt colum and pushed it up into the dash a bit, have a 14 inch and original wheel not sure what one I am going to use yet

I have a build thread with more picture, had to mess with the hood brace as well the way I move the top of the firewall

https://67-72chevytrucks.com/vboard/...d.php?t=828457

[leegreen]

Extending the cowl under the hood looks like a very good solution to add some needed volume behind the dash for AC and wiring. I think you will have to relocate the hood cross stiffener forward a bit?

I don't see 11" added to the floor though? It looks like only 3 or so more in front of the cab mount bolt. What am I missing? 3" is probably enough extra for most.

You'd need either extremely long legs or a much more recumbent seat setup to need 11" more leg room, human ergonomics have not changed much since the 50s. I'd guess power steering has encouraged us to sit further from the wheel, and diet has impacted how roomy it is between seat and wheel.

[70chev383]

I did have to move the hood brace
My truck was a 1 3/4 so had the big fenders not sure is the bottom of the fire wall is kicked back farther then the 1/2 ton, from what I’ve seen in pictures the inner fender are pushed farther into the firewall, I can find any pictures but when I started the bottom of the fire wall was right at the front cab mount bolt,
Didn’t need to but wanted to push as far forward as I could, trucks got a visor on it so wanted to sit low in it

[leegreen]

that is interesting, popular opinion is that the cabs are identical. Except for COE

in post 69, your third picture, I'd put the half ton toeboard at about the middle of the three beads rolled into your new floor

[70chev383]

Went out and measured, bottom of firewall to back of the cab was 55 inches,

[leegreen]

From my floor mat at front to the upholstery panel mounted to the rear cab stiffeners I get 50". Maybe 1" more if I was able to measure steel-steel.

So a stock 1/2 ton cab is 50- 51" at the dimension shown in red here.




If you are at 55", you have a nice 5" extra. If you added 11" to get there your original floor must have ended just under the dash!