identification · FF-0420

How can you tell a 21-stud Flathead head at a glance?

Look below the spark plugs. On a 21-stud engine there is one bolt below every spark plug; the later Flatheads have two there.

Expert

Ed Smith

Evidence

expert attributed

Component

cylinder head studs

Applicable scope

Ford Flathead V8, 21-stud heads compared with later 24-stud heads