Hello,

There should be a part number stamped into the top of the head near the center of the head on the side with the intake and exhaust ports.

There were 4 "F" heads and all of them measured 3.42" in thickness measured from a head bolt hole to the cylinder head gasket surface that I am aware of and 3 out of 4 are easily identifiable by certain features.

A 1973 "F" head will still have the holes to mount the auxially air valve and the water temperature sensor, both for the Djet fuel injection and will have an extra threaded hole on top of the head towards the front near the #1 fuel injector port and this hole is for the power steering bracket which became an available option starting in 1973 for the Volvo 140 series car.

A 1974 "F" head will still have the extra threaded hole near the #1 injector port, but the head will not have any holes where the auxially air slide or the water temperature sensor were mounted on the 1973.

And the 1975 "F" head will have the extra threaded hole for the power steering bracket and a single threaded hole where the auxially air valve was mounted and this threaded hole is for the smog pump that came on the 1975 245.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90501