Setting ignition timing correctly on a classic C10 SBC is critical for performance, fuel economy, and preventing detonation. Yet it’s one of the most misunderstood aspects of classic truck tuning — especially when vacuum advance is in the picture.
This thread covers finding TDC, reading timing marks, static vs running timing procedure, manifold vs ported vacuum advance, and what total timing you should target for pump gas on a street SBC. We also discuss the difference between mechanical advance curve and vacuum advance.
For trucks that have already upgraded to HEI ignition, check our thread on the Best HEI Distributor for Classic SBC — proper timing procedure is covered there as well.
What timing are you running on your classic C10 SBC and what vacuum advance setup?