XP to XR 3speed gearbox upgrade mods needed

[XPFalcon1966]

Hi
I have an XP with a leaking 3speed gearbox and finding it hard to get it in gear.
Thinking of putting an XR 3 speed synchro in.
Does anyone know what has to be modified for it to work?
Is it worthwhile?
Thanks Heaps
Darryl

[Citroënbender]

It’s the “large back” type block, like an XR?

[XPFalcon1966]

I’m not really sure.
It’s an original 170 pursuit.
It has an original 3 speed non synchro gearbox. 4 bolt holes on the top of the gearbox.
Someone told me that it’s best to put a later model gearbox out of an XR falcon.
It’s a much stronger box with synchro in first gear.
Just wondering what modifications I need to make it work for me?
Cheers Darryl

[Citroënbender]

That might be the small bellhousing type block unless it’s a very late XP, if so you’ll not find it straightforward to put the later box in. Having the selector shafts and their bushings rehabilitated could be an easier choice.

[Itsme]

I got caught out once with the difference size bell housing on an XM ute, very frustrating.
Do some measurements to check before proceeding.