Q: I’ve purchased a new harmonic balancer for the small block in my 1965 Mustang. There are three separate sets of degree marks on the balancer. Which should I use to set my ignition timing?

A: Ford used three different Top Dead Center (TDC) locations on its small block engines. So, some harmonic balancers have three sets of marks to accommodate the different timing pointer locations (10, 11, or 2 o’clock). If you have your original balancer, line up the crankshaft keyways and highlight the appropriate marks on your new balancer. Or, you can simply rotate the crankshaft keyway on the 12 o’clock position (TDC #1 cylinder), install the balancer, and highlight the marks that align with your timing pointer.

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all

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Author: Dave Matthews

Dave Matthews was a mechanic for the U.S. Army, a Ford dealership, and served for many years as a fleet mechanic for construction companies. Now a technical content producer at Summit Racing, Dave has spent decades working on everything from military vehicles to high performance race machines.