That wasn't my experience Thom, my combo consists of an EA T5, very old mechanical toploader bell drilled and studded to suit, and standard 351 clutch. Input shaft on my T5 was the same length as the single rail that came out, 6 and 8 cyl types, only mod was to skim 1.5mm off the diameter of the input bearing retainer (snout) to fit into the smaller hole in the bellhousing.
This same T5 box lived in my EF and my EA before it, both of them 6s.
You can use a 6 cylinder t5 on a single rail or top loader bellhousing using an adapter, the 6 cylinder t5 has a longer input shaft than a v8 top loader or single rail, all e series t5's are about the same strength, hp doesn't really kill t5's torque does a mild 302 in front of one in a light car like an xp should have a pretty decent service life, the only reason to chase up a factory V8 t5 set-up would be for the left hand starter but then that restricts off the shelf header/exhaust manifold fitments on the passenger side and limits you to a cable style clutch
i don't know what other options are out there, but i once saw a 250 crossflow with a V8 commodore box adapted to it(was in a transit van) on a dellow or CRS bell housing.
not sure why that was done,
the 6cyl T5 bolts up to the single rail/top loader v8 bell housing with some reasonably easy mods @gerg did.
i wonder if an importer like eagle spares would have a box from one of the Chev C10 trucks etc(shifter forward more, could be an option also)
the manual conversion stuff has always been dear.
HA HA HA.....thanks Thom, as soon as I find that winning lottery ticket I bought. Cant even find a good V8 manual 5 speed.. Reckon I might have to get one out of a XR6 or similar, and down size the horsepower of the engine.