Get an accurate measurement of the height of the cylinder head from the
headgasket surface to the valve cover gasket surface and we can tell you
which it is (assuming it has not been changed or milled too much.

While you're doing that copy down the number on the block just below
the head near the distributor. It will start with 49 and followed by
other numbers. The 49 and the next 4 digits after that are the type
and the remainder are engine serial numbers.

These two things will enable us to confirm whether the head and block
match as well as whether the head (which is what really makes the
difference) is B20E or F.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma