Yep, that’s why Sportsmobile only uses aluminum bumpers (Aluminess Brand). The conversion adds weight but it also adds to the front axle GAWR. You can look at all the 4x4 Van sites on the internet and find conversion vans slightly to massively over the GVWR all day long.
2003 Ford E-350SD 4x4
V10 / 4R100 / NV271
Front Axle - 1 Ton Spec Dana 60 / King Pin / Open Knuckle / High Steer
Rear Axle - 1 Ton Spec Dana 60 / Full Floating
Eaton E-Lockers Front And Rear / 4:10 Gears
ARB Differential Covers / Nodular Iron With Dipstick And Drain Plug
Leaf Spring Suspension Front And Rear
46 Gal Transfer-Flow Fuel Tank
ExtremeAire Magnum Air Compressor
Reunel Rear Bumper
On And On ...