Not many of the M2 IFS kits are designed to handle the weight of a truck w/ a load in the back; and there are very few places to find tonner parts. As mentioned in another thread, the tonner frames are longer and beefier, the spring shackles are larger and farther apart. However, if you are planning to rip out everything below the framerails, I don't see that it will make any difference.
For carrying capacity, you might want to look at harvesting a GM IFS from a late 70's - early 80's truck. It seems to be the simplest, most cost effective option and should permit hauling without taxing the hardware.
Here\'s some reading material for ya, there's a few different approaches to IFS covered in there. Remember, any parts you can't find a use for should go in the
Swap Meet, as some of us are still bouncing along on straightaxles. :p
