I have a similar plan
, but because I,m using a J-10 pickup frame all of my mounts are custom.
I blocked the body up off the frame far enough to clear the drivetrain components, but as close to the frame as I could, then built the mounts using a 1.5" poly bushing between the body & frame, positioning them as close to the original mounting locations as possible
!
As to the question of body stiffening, I bent 14 ga. hat channels to tie the existing bodies together ( overlaping the OEM support channels in both bodies) & supporting the new floor area
!
There are pieces of channel running accross the body (between the hat channels) to add torsional ridgidity!
And finally I'll use 1/8" or 3/16" diamond plate along the rockers, extending from the bottom of the door openings to about 3" below the bottom lip of the body with a 90* turn to the outside to form a step!
That will help hide the gap between the body & frame & add some stiffness as well!
I'll either incorporate them into sliders or boat sides
!
Just a thought: If I build boat sides back to the frame, that will in effect tie the body & frame together ridgidly & elliminate the need for any kind of flexible body mounts!
Right??