Eric,
From what I have read and saw over the years, the face of the fan setting 3/4" from the radiator is the SWEET spot that everyone shoots for.
That would make sence as to why you couldnt get a socket on the old one it was prob. settin in that range that is the most preffered.
I would use the spacer if it was me.
Just my 2 pennies
Tim
