Looking into this, and it seems to be feasible [^]
Gearbox is a Lexus IS200 6 speed with a .86 top ratio, so it;s like an overdrive. And it nicely bridges big gap between 3rd and 4th on the Commer box.
Easily available and reasonably cheap too, rated for 200 bhp +
Just need to get a clutch plate and then think about the best way of doing it
If anyone is interested then say so, then i will make jigs and patterns as i go along, otherwise i won't bother
"You,re only supposed to blow the bloody SLIDING doors off"