Finally today I had the opportunity to put the 915 and G50 ('87-'89 model) next to each other and I thought you guys might find this interesting as well.
Axles/CV-flanges on exactly the same level:
Difference in length measured at the nose cone where it hits the torsion tube is then 3,5 cm.
Scenario when belllhousing is level, but when the G50 has had its bellhousing shortenend up to the first rib, so I have put it one rib backwards:
Difference in length is then a mere 1,5 cm:
So its still longer, but only a little, when you shorten the bellhousing (which may also implicate the need to have the input axis shortenend as well, which fyi requires complete disassembly..).
Other interesting fact was that the width from axle flange to axle flange is 25,0cm for the 915 and 24,8cm for the G50! So its virtually equally wide.