Steering box (ZF, made in Germany) is DIN metric... won't need to mess with that other than adding oil and that's just a little plastic plug you pry out.

Brake caliper to adaptor bolts, again, metric but you shouldn't need to mess with those unless you fry a wheel bearing.

SU carbs (unless you have the HIF44) are NOT metric but some fittings are wonky Whitworth on the older H6 (which you shouldn't have).

Previous PO may have inserted the odd metric bolt or two... mine used two 8mm bolts for two of the tranny bell-housing to engine bolts for some reason (probably mis-information).

For some odd reason my fuel tap was metric, 15mm and 14mm. Dunno why (and my observation has been questioned) but again, that is a spot you won't need to mess with unless you are extremely unlucky.

That about boils it.

And I think the SAE connection was through Britain, not the US... at least at that time.

Oh, tools...
Spark plug socket and socket handle. One short extension. Philips and standard screwdrivers. One very small screwdriver for tightening/adjusting the itty bitty screw on the wiper arm. Feeler gauge set (or individual leaves proper for your ignition and tappet clearance). One set open end wrenches and box-end wrenches (you always seem to need both), adjustable wrench (crescent wrench) needle-nose pliers, Big vice-grips, small mallet, slip-joint pliers.
I fit all that and more in a small (7.56mm NATO) ammo box. The "more" is bits of hose, wire, wood tool handle segment for bashing, etc...

--
Mike!