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Greg Jones · 03-31-2015, 09:07 PM

Your point gap is a little wide-range should be 0.018 to 0.022. A wider gap will advance your timing. Your rotor to cap gap should be a minimum of 0.025 and some go wider. Do a search on timing posts on the Model A forum posted by Purdy Swoft and Tom Wesenberg. Pay close attention to what they say about taking backlash into account.

As to vacuum I have never used a vacuum gage on a Model A so am of no help there. Regarding the spark advance lever: if you have a stock 4.22:1 Model A head, then advance to about 3/4 or slightly more for highway speeds. Higher compression heads require less advance. My 5.5 Snyder head on one engine I can advance to roughly "2/3" while my 6.0 Snyder on a different engine runs best at highway speeds (55 mph) just slightly under 1/2 advance. YMMV as they say......

03-31-2015, 09:07 PM	#3
Greg Jones Senior Member Join Date: Jul 2010 Location: Aiken, South Carolina Posts: 698	Re: Timing and vacuum Your point gap is a little wide-range should be 0.018 to 0.022. A wider gap will advance your timing. Your rotor to cap gap should be a minimum of 0.025 and some go wider. Do a search on timing posts on the Model A forum posted by Purdy Swoft and Tom Wesenberg. Pay close attention to what they say about taking backlash into account. As to vacuum I have never used a vacuum gage on a Model A so am of no help there. Regarding the spark advance lever: if you have a stock 4.22:1 Model A head, then advance to about 3/4 or slightly more for highway speeds. Higher compression heads require less advance. My 5.5 Snyder head on one engine I can advance to roughly "2/3" while my 6.0 Snyder on a different engine runs best at highway speeds (55 mph) just slightly under 1/2 advance. YMMV as they say......