[greguw]

I did consider the hucks ... The bolts were there just for assembly and lining stuff up ... Everything is welded in place , plus the bolts are grade 9 ... there almost ARP stud strength over 200,000 psi , not much stretching going on there .

The frame thickness was best around 88 to 1990 ... yes that was the old body style . Think it ranged from .190 to .210 ... the K30 were the best for the cummins conversions , there .230 ... allmost a 1/4 thick . They all flex with the weight of the cummins . If your not hard core offraoding its not a big issue .

I have seen guys get away with 3 inch lift ... biggest thing is the front driveshaft contact with pan ... its close . really depends on the motor mounts you run . I did the 1" aluminum body lift and that was perfect from my build .
I have the custom deavers ... really now with all my weight I am 8 to 9 lift body and all my springs did settle but are going to ride and work better than stock .
The 8 lug will be fine ... unless your wheeling then dana 60's are pretty cheap right now .
Gears depends on your transmission ... with 33 to 35 3.73 or 4:10 would be fine ... stock these 12 valves max out at around 2200 rpms .
I have put a lot of time in this build , its going on a year now , my big concern was a rust free truck . Truck was a little more than I though , I owned a automotive shop for 20yrs so I can build just about anything ... I forgot how much time and money goes into toys like this ... I'm over 30K and will dump another 3k in paint and body .
Todays my birthday and I will be picking at the truck for a couple hours today ... I have been doing 3 hrs everyday and say 6 hrs on weekends .
Not to sway you away from doing your build , these trucks are alot of work and its not cheap to build a diesel .