47-55.1 Stretching the cab

[8man]

I've seen instructions on chopping the top, and Jim did an excellent write up on making a convertible, but I'm looking to add about 6" to the 54 cab so I can move the seat back a little for some more foot/leg room. I was thinking behind the doors, but don't know where to stop the cut, add to the roof, etc.

Does anyone know of someone who has done this? I'd like to get an idea of what I'm in for before I get too far down that rabbit hole.

I know I'm supposed to finish the 48, but I'm stuck inside for a couple of days and need something to occupy my mind.

Thanks.

[duramax55]

8man hi if i was to do that i would cut the doors and cab in half and extend that way. i know it is a lot more work than extending the back only but looks way better. would need a donner cab

[joedoh]

i havent done this but i have thought about it a fair bit and if i ever did the job i would PROBABLY use two cabs, mark a center line on them at the mid point of the roof and cut one 3" forward of the line and the other 3" rearward of the line. then weld the two long sections together. my theory is that it would minimize the amount of fab needed, only one seam instead of two to keep straight. if you did it to the doors the same way it should help there too. you would end up with a complete shorty cab too which would be kind of useless but funny enough to make a kids playhouse or something with.

that said, I dont know that you would need a full 6 ", there is a truck in jims project thread that was stretched 2", it looks right and in person the interior is cavernous, lots more room.

[Dan in Pasadena]

I like your idea but I think over 3" there would be too much change in the curved profile. Unless you're 6'-6" or taller I'd THINK 2 - 4 inches total would be plenty. Yeah, "....if I'm already doing 2" why not...."

I get it but a small change is a big deal to get truly unnoticeable body work. 3" total or 1-1/2" per cab might be the sweet spot.

[mongocanfly]

i think i would do like Russ stated...or just add a section in the middle of door and roof

can anybody remember the guys name that did that here a few yrs ago...he had a very nice build

found it... here it is... plus 5
http://67-72chevytrucks.com/vboard/s...hlight=stretch

[dsraven]

I have added 16" to my 57 cab. it is behind the doors so that left a decent sized small window opening there. if doing it again I would do the 16: through the door instead. otherwise it seems like you are sitting at the B pillar. you gotta look at the roof though because it is the hard part. if it were a square roof it would be easier but mine is like extending an egg. yours is likely no different. it tapers to the front plus has the dome to deal with so if you did like joedoh says, with 2 cabs cut at the same place then the dome would theoretically be the same shape there. I also highly recommend a tig welder as the welds are softer and lots of time so things don't stretch or shink out of hand. martin sr (Brian, he's a pro bodyman) would say weld the whole thing at the same time so it all expands and shrinks the same amount. maybe pm him as he has done roofs before. i recommend to grab a copy of that little book called metal bumping, its old but metal doesn't know that.

[GreasyLikeaBurger]

I remember someone here in the build section had done it. Probably a few years ago.

[8man]

Thank you all. I am just "thinking" about this right now, but you all seem to be in agreement that through the doors is the place to go, IF I do it.

I am going to finish the 48 and see how much I need, if any, I'm 6'3" and may not need it.

I'm going to the thread that was posted and I'll look at what all is involved before I make any decisions.

Thank you all again, now I have something to think about until I get back on the 48.

[8man]

Mongo, THANK YOU FOR THAT THREAD! That guy's work is awesome. So well thought out and then executed. I would love to see that truck in person.

[joedoh]

Originally Posted by 8man

see how much I need, if any, I'm 6'3" and may not need it.

its been my experience that its not height that is the limiter, its width

i am 6' and when i use a 88-93 bench and move the gas tank outside, I lower the 88-93 bench stands 1" and everything is golden, lots of room especially between the seat and steering wheel (see "width" )


that truck mongo posted is awesome, i wonder if he finished it?

[8man]

Joe, thanks for the thoughts, but the width is fine, it's the leg and arm length that I was thinking about. With the seat in it, I think the arm length is good, but the legs are feeling a little cramped.

I wondered it he had finished as well. Some very fine work and planning there.

[mongocanfly]

It shows he was logged on a couple weeks ago...so maybe he is still having around and doing well

[joedoh]

Originally Posted by 8man

Joe, thanks for the thoughts, but the width is fine, it's the leg and arm length that I was thinking about. With the seat in it, I think the arm length is good, but the legs are feeling a little cramped.

haha i should sugar coat less. by width I meant waistline. I am careful with spacing for the steering-to-gut measurement because buyers are sometimes.. corpulent

[mr48chev]

Wow that just added a lot more work to my cab stretch than I was figuring on.

I've always planned to go 9-1/4 inches and use the GMC long bed half ton fame I have with my short box and long bed running boards.

I intend to use two doors to do the stretch rather than install a panel with two weld seams. One reason is that I have a lot of extra doors.

I've subscribed to Donandal's thread and will probably be studying that thread and using a lot of what he did. It showed me that the idea that I had on how to do it isn't gong to work out right. Thanks to Mongocanfly for finding and sharing that.

[_Ogre]

Originally Posted by 8man

I am going to finish the 48 and see how much I need, if any, I'm 6'3" and may not need it.

i so wanted to stretch my 58 in the doors for legroom, i was 6'4" when i started my project. my 58 cab is a lot roomier than yours, i very much regret not doing it now after 36,000 miles. i was just so tired of fabricating on truk at that point, i just wanted to be done. i did raise the seat 2" over stock and installed a tilt column, that helped a little. i still fold up like a pretzel to get in.

this panel stretched all the doors 6", used 8 doors in the process

[dsraven]

Truck still looks good!
What is your ride height at the rear of the front fender, if you dont mind me asking?

[8man]

That stretch panel is gorgeous!

[mongocanfly]

Agreed , it sure dont look stretched, at least with the doors open, I bet that was interesting

[Tempest67]

Since we are 'spit balling' here.

What do you think of cutting the cowl as a way of 'stretching an AD ?

You would not need to worry about weld seams in the middle of the roof or the doors, not to mention the door mechanisms and glass.

Cut in the cowl, just in front of the hinges (A pillar), cut the floor where it bends up to attach to the firewall, and move the firewall forward.

The downside, getting in and out will not change, but once you are in, there will be plenty of leg room.

Just an idea???

[8man]

Tempest, I was on the same thought process when I started this thread. I have the floor replaced in the 54 but have not reinstalled the firewall for that very reason.

I have to get the 48 done before I get back on it, so I'm still thinking.

[dsraven]

Pretty sure that's been done on this forum someplace. An AD guy remade the firewall to fit his long legs and also the engine setback.

[Tempest67]

my biggest concern will be the overall look of the truck when done. (profile)

Will the 'hood' look too long? and awkward?

but I do like the idea of not having to weld the middle of the roof and doors with filler pieces.


If you give it a try 8man, please keep us posted

[8man]

My thought was not extending the entire firewall as you described, but to extend it on either side of the engine to add foot room. I have not studied the 48 enough to know if this is possible.

On extending the firewall as you discussed, I saw one of the AD cabs that had been widened by 4" at the back and up through the firewall. They added 2" in width to each front fender and to the back, and I studied it for a while, but couldn't find it. My point is that if it were less than 4" and done correctly, I'm not sure it would show up to most people.

[dsraven]

Are you guys talking about a firewall model or a cowl model, where the distance between the windshield and the hood gets longer?

[joedoh]

Originally Posted by Tempest67

my biggest concern will be the overall look of the truck when done. (profile)

Will the 'hood' look too long? and awkward?

but I do like the idea of not having to weld the middle of the roof and doors with filler pieces.

honda did this with the 95-98 accord V6, you can spot a V6 model of those years a mile away because its longer through the hood and front fenders. wikipedia said it was hard to notice without the two side by side (I disagree) so maybe it wouldnt be as noticeable on the AD