There are several reasons not to do this. One front end stability, ie" steering issues. You can get away with a bit of funny business on the front axle, but too much and your steering geometry goes out the window. Real hard to correct it.I know this thread is on lifting bobbed Deuces, but are there any pictures and build ideas/methods on lifting a non-bobbed 3 axle M35A2 with 395's/46 inch tires that just barely fit on the rear tandems?
Second and possibly the strongest reason not to lift is the rear floating suspension system. With the torque rods and the floating spring system you are looking at major surgery on the truck. The torque rods need to be extended first off, then the spring perch needs to be remounted. Not a small issue. Then even if you did "everything" correctly your looking at rear end stability issues. The center of gravity has risen well above safe standards. You can no longer "safely" scale hillsides or traverse gulley's without the constant fear of tipping over.
But hey, it's your truck. Do what makes you happy !