Well, I found that a few have done their Cummins into GMT400 conversions on the K1500 platform Suburban’s using the 47RH w/NP243c t-case horizontal and keeping the IFS w/o any lift and it’s been running that way for 100k+- w/o issues.
One conversion over at 4BT conversions was done by a master tech teaching automotive tech at the college level for 33 years.
He used a 2”x4” ¼” thick tube 48” tube welded 12” each side to the back of the t-bar x-member then cut out the center section of the factory t-bar x-member to within 1” of each key bracket then boxed everything, this gave clearance needed to use the longer Ram Cummins 47RH 4x4 O/D extension w/GM t-case.
His vehicle has no body or suspension lift whatsoever however; he did have to hammer the rear floor area up above the t-case, my floor looks like it would require cutting and fabrication in that area to clear the t-case which is no big deal.
Perhaps, his Cummins is not mounted as far back as mine I just don’t know but my concern is any moving of the t-bar x-member back from its factory position could be a problem ‘he says no’ and thinking I may be able to perhaps space the steel tube away from the t-bar x-member to keep the factory mounting point of the t-bar x-member.
Another modification he used was too remove the rivets from the x-member just behind the t-bar x-member and refasten with grade 8 fasteners this makes the install doable and for later R&R of the Ram Cummins drivetrain if the need were to arise.
I’m looking for input pro or con.