The flipping upside down was on my request. I need to drill holes in the base plate and the bolts connecting the fifth wheel proper to the base plate are immovable (that is, without heavy power tools).
I now also really know why the spacer wood is there: to provide room for the rivets sticking out on top of the chassis. When I saw that and it dawned, I though "o sh.........." That looked like the next #$%^^%$ major problem. The I started measuring and praying and
lo and behold! .. maybe it will all fit after all.
The base plate is 96 cm (37.8") wide, the M51A2 frame 86 cm (33.9"). The holes in the base plate connecting the 5th wheel to the DAF are exactly outisde the farme of the M51A2. Which means I have to drill 12 holes in the base plate and 12 holes in the chassis.
Oops, the bloody rivets mess up everything. Maybe not. See the last two pictures. The last but one shows that the base plate is not a flat plate but what the Dutch call a
damwand profile. The last picture shows the rivets and a piece of cardboard showing where the profile is raised and where it fits onto the chassis. You are looking down on the three most forward rivets from the X cross-member with the left chassis rails, above the tandem.
Hard to see, but the profile just misses all the rivets, with exception of the fourth rivet just outside the left of the picture. That means I have to cut a whee little hole in the bend of the profile, and it will fit perfectly. That will bring the 5th wheel center at 128 cm (50.4") from the end of the chassis. This is a bit before the middle of the tandem.
The first two pictures show the 5th wheel on the orignal truck and is ID tag. This Jost fifht wheel came off a Czech DAF truck, is suitable for over 50 tons, and has EU and Dutch recognition.