Cannot jack up the car to have a look but will be changing the oil in the next couple of days. What spanner/hex key is used. It is in my spider but It is in fact a 2000 out of an Alfetta year 1980
should be a 27mm spanner............but sometimes there is a 12mm hex (allen), depends who was there before you!
have both at hand and you'll be ok
even if it is not 12mm allen you will need the allen for the tranny or rear axle, so it is worth having both! (and a 22mm is useful too for the tranny/axle)
Alfetta sump plug would be 27mm, but you won't likely have an alfetta sump on your alfetta engined spider anyway.