If H is for Hitachi what is R (as in R160, R180 and R200) for?

Just as a little aside if you want to know the type of diff and ratio fitted to a particular vehicle, look at the trans section of the ID plate and the following table applies :-

HA= H150
HB = H150A
HC = H165B
HD =H190 (aluminium carrier)
HE = H190 (iron carrier)
HF = H190 A (reinforced iron carrier)
HG = H233B (Urvan diff)
RA= R160
RB = R180
RC = R200
CA = C200
CB = C216
The number after these letters is the diff ratio - eg HC41 - H165B with 4.1 gears
HA41 = H150 with 4.1 gears.
Another piece of useless information for the brain cells. Doh! my D drive hurts!