frames, 4x2 vs 4x4
Moderator & parts slinger
Joined: Feb 2007
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From: S/W Missouri, Polk county
I believe they are the same overall dimensions, but 2wd and 4wd frames are different. read into this, the differences are mentioned.
There is nothing nuts and bolts about a 4wd conversion, there is not a thing that is bolt on or swappable. The engine cross members are entirely different, and this means that if an un molested truck is what you are after, it will be impossible to create one with a 2wd platform.
The 2wd will have to be lifted quite a way to clear the front diff. 2wd trucks are coil sprung and most F250 4wd's are leaf sprung. None of the suspension items are even close to the same, so you will be fabricating or modifying some original 4wd stuff to work.
Steering systems are entirely different as well, so you will be upgrading that too.
My last conversion with leafs ran me several thousand dollars, and that was with the work that I performed for free. The difference in sale values between a 4wd and 2wd are minimal, and the 4wd conversion is hardly justifiable.
Well the frames are similar, with a few exceptions. The frame horns are slightly different, and the frame widths aft of the cab are different from 73 to 77 trucks. The frame rise is also slightly different, but this is not a show stopper and does not make much difference one the fabrication begins.
Now the important question is whether or not you will be using a coils springs or a leaf spring. It is possible to install a 78/9 radius arm and suspension. Not a big deal really, and with a standard cab this is reasonable. Not quite as easy with a super cab and or crew cab.
The 2wd frames are not cut for the shackle pivot, and they do not have the provisions for a spring hanger, but again, this is not a deal breaker. Installing a pivot is just a tedious process, accuracy is key.
Ok, so next is the transfer case. You have two choices, install a married case, and this requires the proper transmission. Might find some difficulty making or modifying an output shaft to accommodate the early C6 and a married transfer case. So then the next option is to find a divorced transfer case, and install this. You will have to make up a cross member, but then you will have to get creative with the shifter linkage. See the 4wd trans will have an adapter or tailshaft with a pivot for a typical 205 shifter. Fabrication is the only limiting factor here.
Next and final factor will be the speedo. See your speedo works from the trans, so that being the case, you will have to get a speed reference from the t-case. If you do not, the speedo will read twice as fast when you put the case in low range. But you will be in 4 low so who cares how fast you are going.
As mentioned the steering box will have to be relocated, and the truck will require some lift. That engine crossmember has limited clearance so you will be looking at some lift to even clear it. The other option would be to remove it and replace it with a tubular unit.
There is nothing nuts and bolts about a 4wd conversion, there is not a thing that is bolt on or swappable. The engine cross members are entirely different, and this means that if an un molested truck is what you are after, it will be impossible to create one with a 2wd platform.
The 2wd will have to be lifted quite a way to clear the front diff. 2wd trucks are coil sprung and most F250 4wd's are leaf sprung. None of the suspension items are even close to the same, so you will be fabricating or modifying some original 4wd stuff to work.
Steering systems are entirely different as well, so you will be upgrading that too.
My last conversion with leafs ran me several thousand dollars, and that was with the work that I performed for free. The difference in sale values between a 4wd and 2wd are minimal, and the 4wd conversion is hardly justifiable.
Well the frames are similar, with a few exceptions. The frame horns are slightly different, and the frame widths aft of the cab are different from 73 to 77 trucks. The frame rise is also slightly different, but this is not a show stopper and does not make much difference one the fabrication begins.
Now the important question is whether or not you will be using a coils springs or a leaf spring. It is possible to install a 78/9 radius arm and suspension. Not a big deal really, and with a standard cab this is reasonable. Not quite as easy with a super cab and or crew cab.
The 2wd frames are not cut for the shackle pivot, and they do not have the provisions for a spring hanger, but again, this is not a deal breaker. Installing a pivot is just a tedious process, accuracy is key.
Ok, so next is the transfer case. You have two choices, install a married case, and this requires the proper transmission. Might find some difficulty making or modifying an output shaft to accommodate the early C6 and a married transfer case. So then the next option is to find a divorced transfer case, and install this. You will have to make up a cross member, but then you will have to get creative with the shifter linkage. See the 4wd trans will have an adapter or tailshaft with a pivot for a typical 205 shifter. Fabrication is the only limiting factor here.
Next and final factor will be the speedo. See your speedo works from the trans, so that being the case, you will have to get a speed reference from the t-case. If you do not, the speedo will read twice as fast when you put the case in low range. But you will be in 4 low so who cares how fast you are going.
As mentioned the steering box will have to be relocated, and the truck will require some lift. That engine crossmember has limited clearance so you will be looking at some lift to even clear it. The other option would be to remove it and replace it with a tubular unit.
Lead Driver
Joined: Mar 2010
Posts: 5,250
Likes: 11
From: West Virginia
The frames are different in a lot of ways, on my 4wd f150's, the cross members were attached by braces back to the frame and on a 2wd f100 I scavenged parts off of in a junkyard, not only was the frame stamped of a thinner metal, the height of the frame was shorter, and the brackets that attached the crossmembers attached completely differently and only used about half the frame height.
And I measured a supercab long bed 4wd frame off a 3/4 ton, a 78 f250 4wd, a 77 supercab 2wd, and a 78 f150 4wd frame (owned all at one time and was looking to monster mash some frame parts) and all turned out to have different frame heights.
I don't know the exact reason you're asking but aside from the obvious differences, there are bound to be many other changes from one model to another, the types of things that make you scratch your head and wonder why.
And I measured a supercab long bed 4wd frame off a 3/4 ton, a 78 f250 4wd, a 77 supercab 2wd, and a 78 f150 4wd frame (owned all at one time and was looking to monster mash some frame parts) and all turned out to have different frame heights.
I don't know the exact reason you're asking but aside from the obvious differences, there are bound to be many other changes from one model to another, the types of things that make you scratch your head and wonder why.
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