Can 4-speed 915 be converted to 5-speed?
 

In Peter Morgan's book he says, "the fifth speed was housed with reverse in the end cover, while on the four speed alternative the fifth gear wheel was simply deleted from the end of the gear set."

Does this mean that a 4-speed 915 could be converted to a 5-speed without too much difficulty? There must be more to it!

Thanks

yes, mind you from memory 2nd 3rd and 4th all have to be changed to different ratios to do it properly.
so although it's simple the cost of the other gears plus whatever 'while you're in there' work make it fairly costly :(