My bus has always had a lack of go! It's an 88 E plate 1.9 it did have an early 1.9 fitted with solex carb, can't remember the number now! (getting old both me and the van)
So we fitted a DG which was supposed to be correct for the year, good comp. new rings etc etc. tried everything but still no good.
Goes down hills fine though HaHaHa

Revs well in 1st and 2nd but seems to loose all it's built up by the time you get to 3rd and 4th not much between them either?
So I'm thinking maybe is it possible it has the wrong box?