Ford Bronco Ignition Timing Curve Table - RPM vs Vacuum Advance (12° Base)

This document is a spreadsheet-style ignition timing curve table. It states a base timing of 12 degrees and maps total ignition advance across engine RPM (rows from 500 to 4500 RPM in 250 RPM increments) and vacuum values (columns 0 through 14). A yellow-highlighted column beside the RPM values shows the mechanical (centrifugal) advance contribution at each RPM, starting at 0 at 500 RPM and reaching a maximum of 22 by 2750 RPM. A yellow-highlighted row under the vacuum headers shows the vacuum advance contribution, remaining 0 through vacuum values 0-8, then rising to 1, 5, 7, 11, 14, and 14 at vacuum values 9 through 14. The body of the table gives the resulting total advance for each RPM/vacuum combination, ranging from 12 degrees (500 RPM, low vacuum) to a maximum of 48 degrees (2750+ RPM at high vacuum). Advance is fully in by 2750 RPM, above which the values are constant for a given vacuum column. The table does not identify a specific vehicle, engine, distributor part number, or model year; the attribution to a 1985 Ford Bronco comes only from the uploader.