the exhaust fittings originally were all on the chassis
the first is just after the lower panel, the one about half way along and was a metal plate, and then the exhaust fitting was bolted on there, the last one was on the drivers side on the chassis just by the rear wheel arch, and again was a bracket welded onto the chassis
over the years these brackets tended to come off so the exhaust can be fitted by straps on the rear lower panel cab panel, and the rear floor area on the drivers side
you can mount the exhaust via straps on the outer part of the lower panel, the rear part of the cab
when you look under the van, the upper and lower cab panel are bolted together, you can hang a strap from one of the bolts