Not to hi-jack this thread... I put a complete gear reduction system on my 1984 C165 and did not shorten anything. Aside from the need of drilling two wholes, this is a plug-n-play installation.
BTW, do you know if there is anything else I might need? I'm wanting to adapt to 1984 C Series Tractor? The conversions I've seen on the Forum show a pair of extra mounting holes in the frame and that's about it. Can it be that simple?
Thanks