[WyoAndy]

Robin,

I measured my chassis from the rear of the frame rails. Here are the dimensions:

1 3/16" (Rear Cross sill under Tailgate)
20 7/8"
47 1/16"
72 1/8"

If you have the cross sills the holes are punched so that the sill can be used in any of the three positions under the bed (one part fits all). Remember that there is a metal plate and a 1/4" rubber plate under the cross sill. No wood blocks are used on the 1954.
That is in inches (sorry my metric is a little rusty!)

I "boxed" my chassis so I will have to use extra long bolts and go all the way through the frame rail or figure out some other way.

Let me take some pictures and post them.

Andy