there are plenty of 1500's running around with the full size cummins 12v's in them..

just need the diesel springs for proper ride height with the extra weight, and the drive train needs replaced completely...

(if 4x4, you need a D60 front, D70 or D80 rear, 241DHD xfer case, diesel drivelines, diesel transmission, and should be good)

if you keep stock 12v power you can get away with the weaker rear ends and xfer cases...but if you want to build it up anywhere near like I did to mine, you need a D80 rear, and all of the HD drive train + upgraded clutch, and supporting engine mods for the power...It's simple to build up the diesels, but it's not exactly cheap. my truck wasn't built to what it is now overnight...it's been several years in the making...

 

Well you would have a weak 2500 frame, if you want to look at it that way, but the straight 2500 and 1500 frames are the EXACT SAME FRAMES, no difference in them AT ALL. The 3500 frames are the same EXCEPT for a different rear spring mount, and rumour has it ( I haven't verified this one yet) that some have a extra crossmember, under the fuel tanks...

Just like chevy, and ford, dodge rebadged their light duty 2500 as a 1500, to get into California past the emissions controls. Now alot of 2500s have a better rear axle, but I've seen plenty floating around with the Chrysler 9.25 axle, and 5bolt rims, but they are not rated higher for payload, only towing capacity.