Hi All, I'm very nearly at the stage when I can put the welder away and start filling and spraying the our 89 B250. The interior which was a Bivouac conversion has suffered over the years and so has to come out, and so I'll be refitting it . As such we've been looking at replacement carpet on RockAuto site ( they ship to the UK), and so I have a few questions that I hope you can help with: I've measured the van wheel centre to wheel centre and come up with 128 inches, when I look for carpet sets it shows 107, 121 and 147 as available wheelbases. This is under the listing for ACC Essex with mass backing. Firstly, what, if anything, am I doing wrong to not get one of these figures - or does the measurement get taken from somewhere else? Secondly - has anyone got any experience of this product? Lastly what's mass backing? The van has a type of polystyrene in the bed area, but nothing in the driver passenger area. Is it something like this? Thanks in advance.