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Moving cab backward on frame a couple inches

CyberSniper

CyberSniper

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Anyone ever move the cab back on the frame a couple inches?

I'm putting a truck cab on a K5 frame. The only "original" mounts I was planning on using were the front cab mounts. I planned on making new/modifying the old mounts for the custom core support. And the back of the cab... that's self-explanatory.

So, anyone ever try this?

I was thinking about moving it back because:
Get some more weight off the front tires (front axle is already going forward a couple inches)
Between moving the cab backward 2" and the front axle forward 2" I should be able to fit 44s with 4" of lift if my guestimating is correct (less cutting with smaller tires)
It's relatively easy to change where the mounts are since all I'd have to do is cut out some rivits and drill some new holes


Problems I foresee:
Shift linkage (auto trans)
Steering column length
Transfer case to cab clearance issues (clocked 241)
Transfer case shift linkage
Narrowed front fenders might not reach all the way to the core support
 
are you planning it move the engine back with it? If your going to move the cab back, you mind as well take the engine back too /forums/images/graemlins/dunno.gif
 
you might as well just tube it out, you will have to lengthen so many things, is there any reason you want to have a cab?? street legality??
 
Even though moving the motor back would make the f/r weight ratio even closer to 50/50 I'm not sure if I want to do it. Seems to me that the rear driveshaft would start getting shorter than the front if I did that. I'm planning on running a 700R4/NP241 combination so the front shaft is already pretty long and then the front axle going forward a couple inches makes it even longer.

I don't know, what are your thoughts?
 
Michigan is primarily mud and water... with a bit of cold thrown in. Geologically, the state is a giant basin so it's pretty much just every other state's run-off sediment.

Where I'm at now a 110-135" wheelbase dominates... shorter isn't always better. The things that hinder you the most seems to be the four corners (primarily the front two) and body damage. Tube chassis would make sense going by my description except the mud, water, and cold part...

But I plan on driving this thing. As long as it's within an hour's drive and doesn't involve the expressway I plan on driving it. I know I could get a tube chassis certified in the state of Michigan (it's actually pretty easy, have done it with a sandrail before) but driving it down the road would be a nuissance due to the popo. As long as I run removable drop bumpers and giant mudflaps with quiet exhaust the cops should leave me alone. The current plan for bumpers is to have them pinned so they can go from hanging down to pointing up and the mud flaps to be pinned and removable.
 
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Even though moving the motor back would make the f/r weight ratio even closer to 50/50 I'm not sure if I want to do it. Seems to me that the rear driveshaft would start getting shorter than the front if I did that. I'm planning on running a 700R4/NP241 combination so the front shaft is already pretty long and then the front axle going forward a couple inches makes it even longer.

I don't know, what are your thoughts?

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do you have the tranny/transfercase yet? if you did, you could move the cab back, like you said you were, then bolt the tranny/transfercase up, to see where it would be in relation to the motor and axle. Then use that to visualize how much it will effect the length by moving the engine rearward.

I'd say do it if you think the driveshaft length woulkd be okay, but if your worried than just forget about it... /forums/images/graemlins/dunno.gif
 
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Narrowed front fenders might not reach all the way to the core support


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This might be a problem for you. My core pulled back enough that I was forced to use electric fans as the manual would not fit anymore. 2 more inches might not work.
 
I was wondering about that...

How close is your radiator to the grille?

I'm planning on using a 1/2" square tube grille I've got and cut it to fit then move the radiator as close as I can get to the grille.
 
I put a truck cab on my K5, and it was back 12" (twelve inches). I lost interest and threw it away. I used the stock auto tranny shifter and bent it differently and put it in the steering column hole backwards of stock so it wouldn't bind, it worked flawlessly. For the steering column length I cut the steering shaft where it is hollow and slid a peice of 3/4" diameter solid steel insert into it to space it out and welded it back up.

Are you good at body work? Get some extra fenders and hood and cut a peice out of them right above the axle, then cut yours and lengthen them with the peice from the donors.
 
That might work. The radiator is held in by the stock stuff and the grill spacing is also stock.

I had thought about going to an AL radiator. That could save about an inch or so.
 
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12" (twelve inches).

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/forums/images/graemlins/histerical.gif we're not in elementary schoool anymore, we know what " means! /forums/images/graemlins/histerical.gif /forums/images/graemlins/histerical.gif


Just jerking your feathers dood /forums/images/graemlins/histerical.gif
 
hmm... so you've got like 3" between the grill and radiator like stock? I've probably got about 2" between my grill and the ATF cooler which is strapped in front of the AC condensor right in the middle.

I'm figuring that the tube grille will keep the disaster-sized sticks out of the radiator and all I need room for is the radiator and ATF cooler.

What are you thinking?
 
Happen to have any pictures of this?

I'm thinking any more than 4" and it'll look funny. Maybe I'll have to do some more measuring and contemplating. Maybe if I move the cab back 4" and the powertrain back 2"...

The bodywork would be a nightmare because the fenders taper towards the front... lot of compound curves... probably could roll a piece but that's a lot like work for something that'll probably end up mangled anyway.

Current plan is to retain the factory hood hinges and springs (so I'd end up narrowing the fenders pretty much right over the stock axle hub). I figure with the axle going forward and the tires sticking out well past the body that'll suffice.

At least now I know it can be done... how come you scrapped the project?
 
Don't base your decisions on driveshafts. If you SYE the 241 you can get some beastly driveshafts for it that will take the angle. If you can't afford the CV, they might vibrate, but vibration doesn't kill driveshafts. With 4" of lift it probably won't be that bad anyway. The motor slopes back 4* in our trucks from the factory, so the rear driveline angle probably wouldn't be that bad. If I could trade having a horrible front driveline angle for the one that results from you moving the cab and motor backwards a few inches, I'd be in heaven.

Why not move the cab and the whole front clip back and lose 2" of frame completely? What's stopping you from moving the front clip back with the cab? Cut the rivets and move the front cab mount back too if that's what you want to do.

Solve the tranny issue with a cable operated ratchet shifter.
 
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What's stopping you from moving the front clip back with the cab? Cut the rivets and move the front cab mount back too if that's what you want to do.


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the front spring hanger and the body mount are one and the same, moving one back could create serious problems.
 
they're not the same, they come apart, they're only riveted together.

Besides, it's not a fabbing masterpiece to make a front spring hanger even if they didn't.
 
The closer to stock... the cheaper it is.

The front clip is going to go back with the cab. But I want to narrow the front. That makes the core support and grille get really close to the radiator which gets really close to the crankshaft pulley. I'm planning on making a custom core support anyway... in which the distance between the ATF cooler/radiator and the grille is going to be much closer. I know narrowing the front loses you two inches between the radiator and motor in a stock core support setup. I figure I can gain that back. So, I could probably get away with moving the cab back as much as 4" if I moved the motor back 2".

I don't want to shorten the frame because moving the spring hangers in the front for 52" springs pushes them pretty far forward. It also gives me plenty of room to mount a winch and fairlead so they don't stick out past the frame horns. General consensus is that in Michigan you must have a bumper no more than 24" from the ground and it must be a distance away from your tires but not necessarily blocking your tires.
 
These are the only pics i have, they aren't very good. I didn't move the core support back on mine, just made longer "hood mounts". The back of the cab was even with the front of the back tire (38.5). Mine looked really ghetto, it didn't turn out the way I was expecting. The project was put on hold, now I have permanent shoulder damage and can't do a whole lot, so I scrapped it. I was going for extremely light weight, and while pulling it around the yard it rode pretty rough. I wonder though if only 2" would provide enough weight transfer to make it worth the effort? After I was done with mine I wished that i had just left it alone/forums/images/graemlins/confused.gif

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177907-17-04_001.jpg
 
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I don't want to shorten the frame because moving the spring hangers in the front for 52" springs pushes them pretty far forward. It also gives me plenty of room to mount a winch and fairlead so they don't stick out past the frame horns. General consensus is that in Michigan you must have a bumper no more than 24" from the ground and it must be a distance away from your tires but not necessarily blocking your tires.

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You'd love my front bumper then. I can't imagine why you'd want one hanging that low though.
 
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