Body replacing with GMC Sierra 2500HD

[jeepkeep]

Hello M715'ers

I want to hear from you experts about the project am going to do with my truck M715 1968

In my project, my goal is to make my truck powerful, easy to use, lighter, attractive, monster, safe & modern

Here is what am thinking
I going to buy 2002, 2003 or 2004 GMC Sierra 2500HD
6.0 Liter (LQ4), 4L80E transmission, Manual tranfer case not electronic

Then lm going to put my M715 body (cap & bed) to the GM chassis



The difference is 7.5 inches between the cap and bed, which am going to use it for vertical exhaust and LED light bar mount and water tank

Overall advantage:
● Modern Disk brakes system with ABS
● hydraulic steering wheel
● modern rear and front differentials
● better overall electrical system with fuse box
● lighter chassis
● variety rims because of the Bolt pattern
● safe fuel tank, in-tank fuel pump
● upgradable diff ratios, lock and axles
● market availability of all spare parts

What issues am gonna face when I start this ? Do you recommend other truck better than 2500HD?

Thanks all

[jeepkeep]

[maskale]

Issues? Everything. Plus 101 that don't even exist yet. I don't recommend it. However, anything can be done. Its up to your skill level, no offense, but IMO you wouldn't be asking if you knew you could do it.

Also this is assuming you want it to look factory, and not like a hack job. What I mean by factory is that you do such a good job that it doesn't even look like a body swap.

Its far easier to put the running gear from the donor truck on the M frame.

[warthog_cj7]

Agreed on lots of issues merging 2 different trucks.

Check the layout of the frame. M715 is straight under the cab, then bends up under the bed. In my project I'm putting the cab/bed on 1990 Dodge diesel W-350 and the Dodge frame bends up the cab, which required me to french the back of M715 cab to keep the body lines correct.

Another check is the front axle placement on the Ford in relation to the M715 nose assembly and cab. I didn't want to move axles or shorten/lengthen the Dodge frame, which required me to cut and add to the circumference of the wheel wells adding 3" to the back side and also had to cut into the cab to accomodate this change. Lots of sheet metal work.

The other item is how are you going to handle the electrical? I'm currently in progress using all the existing Dodge harnesses, but having to move components, adding in items, and upgrading/replacing items.

The Dodge I went with is 131" wheel base to the 126" of the M715, my plan will be to build an aux fuel tank between cab and bed. Rough math will give about 47gals.

With the format I have going, I have had to touch and modify pretty darn near every component of both the Dodge and the M715 to make work. I have a lot (too much) of time and money invested in this project over 5yrs.

The other thing that has kept me going is, nobody else is going to have the vision I have on this so I have to complete it, else it's a pile of junk to anyone else, as I've had to modify everything.

I haven't put my build thread on here yet, which I really need to.

[venominjected]

Having done an LSx swap into a 1966 C10 (5.3L/4L60e... but same thing really).

Your in over your head.... things that will not work.

ABS/Cruise etc all run via CANBUS thru the dash and are not applicable unless you plan on keeping the ugly modern silverado dash itself.

Manual transfercase 2500 gasser 4L80e will be VERY difficult. (very very low production volume).

Wheel base isn't correct in any platform (regular cab long box being 'closest')

The LS swap (6.0/4L80e) into the m715 platform with CUCV axle swap for disc brakes will be your much cheaper alternative.

Fueling isn't that hard... frame mounted fuel pump will be easier to navigate thru that the Stock OEM one with its 4 safety shutoffs that you will have to find in the wiring harness and jumper out.

You will still have to program all the security VATS, pollution controls etc no matter what direction you go.

If you plan on any type of winching, HD bumpers, offroading etc... plan on rebuilding the front suspension no matter what... the independents on the GMT series trucks are good for suburbia.... bad for anything rougher than gravel.

[Subybaja]

From a previous thread on that subject:
M715 on cucv frame

The issue comes with the under bed toolbox on the M715 bed with certain frames. Some dually frames, and a few others have enough "dip" in them for the bed to work. Others do not. You will need to measure the frame you have in mind to see if it will work.

I seem to recall one member some time ago notching the toolbox to slot down over the frame, but of course you lose the ability to have free and clear storage all the way through.

That was probably Rollie, when he dropped this truck on a '86 Suburban chassis. Note the bed gap.


Same body, now mine, now on a '95 F350 chassis:


The toolbox does not go through. It's just an ammocan-sized box on either side. While it would be nice to store a HiLift in there, I really don't think it's worth hassling over. I mean, any historic value goes completely out the window when you start swapping any mechanicals, so if this was a 1994 Chevy, would you be worried about underbed storage? Would you use a different chassis based on jack storage? Not I...

My frame was shortened (not by me). 2 straight sawzall cuts, 3/4 welded back together. It's held together for several years, but I'll be rewelding and fishplating it this summer.
(I'll also be correcting the cockeyed lift. )

If I was doing it, I'd do a 'Z' cut on each frame channel, stagger the cuts by 8"-12", and do fishplates. Avoid leaving a "fold here" hinge area...




Obviously, I'd do the body swap. Two cuts, shorten the driveshaft, you're done (and have all the gear you wanted anyway).
Why do it the hard way and remount even the suspension, much less swap everything into the 715 frame? KISS.

Despite my KISS comment, I must admit that my firewall is a hacked-up conglomerate of several trucks.

My frame was actually cut in two places on each side, to get the wheelbase and cab-area dip correct. Just left of the spring hanger:


Mine has the ugly modern dash grafted in. Yuk. Necessary for the electronic auto trans, though.


I've got a frame-mounted fuel pump. The stock in-tank is just a pickup now.

I wouldn't even think about using something as new as you're talking. Mine's a '95- perfect combination of FI/lockup TC/simplicity.

You should chop the frame to make it really fit. It will look like a$$ if the bed/cab don't fit the frame right, IMHO.

All that said, I'm really happy with it. Modern 1-ton running gear, 85mph all day happily, 15mpg from FI and a 4-speed auto, local NAPA parts... I'[m not sure I'd tackle it, but I sure am glad some guy in Texas did!

[md1970]

a guy I know is putting a m715 body on a newer dodge cummins pickup chassis. said the wheelbase is +/- 1" cant remember

[maskale]

A crew cab chassis works best, it has a longer dip in it for the bigger cab. The rear part of that dip will work with the M bed. Just move the rear axle forward, cut off what sticks out the back.