Hi I am new to this and maybe some one can explain what I can do

I have a Van Diemen Multisport which I have fitted a black top to running on bike crabs the engine is transverse in the rear canted over 30 degrees forward

It is mated to an early I think IB5 box with a front mounted starter I need to change it to a rear one due to the exhaust fouling on it I need to run the same mountings and linkage as it a special built item otherwise its a major refabricating

Any suggestions?