Flatheads 101: 21 Vs. 24-Stud

I still can’t stop thinking about my time at the Tardel Ranch. Every now and then, a light will flip on and I’ll remember some little tid bit that Vern or Keith taught me. This one is basic and most of you probably already had a handle on it, but I didn’t and thought I would share.

I had always wondered how some seasoned hot rodders could pick a 21 from a 24-stud Ford flathead with a quick glance. In most cases, I wasn’t half way through my count by the time said hot rodder claimed the piece. Thirty seconds with Tardel and I knew the answer.

Check out the above image and pay particular attention to the center studs. On a 21-stud engine, the studs form a straight line. On a 24-stud engine, the studs form an upside down ‘y’. Easy.