Hi Rickard,
Have you considered just ignoring the Marlin pedal box altogether and going with floor mounted pedals such as below
http://www.demon-tweeks.co.uk/motors...dal-assembly-2
This is the route I'm looking at for the future so that I can upgrade to a 90 degree V8 or 60 degree V12 engine without the servo and master cylinder getting in the way of the wider heads and intake manifolds.
The master cylinder and servo would then be low down facing forwards and out of the way of anything. Ot would save you using up the space in the battery box as well