machining · FF-0423

How far can a 21-stud Flathead block be bored?

Ed says 60 over is the maximum. The block was stamped 40 over but measured 60 over; he guesses it was bored to 40 and rebuilt around 1955, then later bored to 60 with the crank turned 20 and 20. It cannot go bigger because the bore would reach the head bolts, and he says pistons are not made beyond that size.

Expert

Ed Smith

Evidence

expert attributed

Component

cylinder bore limit

Applicable scope

1938 Ford Flathead V8, 21-stud, rebuilt to standard 221 cubic inch, as Ed describes it