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73-87 Chevy _ GMC Trucks => Performance => Topic started by: Chuck Step-a-side on December 29, 2019, 10:06:14 AM
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I have a 1984 Chevy Stepside with a freshly installed early model crate motor (1977) and Edelbrock 4 bbl carb. When tuning up the motor do you first set the timing and then adjust the carburetor fuel mixture and idle or adjust the carburetor fuel mixture and idle first and then timing? Thanks, Chuck
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Adjust ignition timing, then idle RPM, then idle mixture.
Disconnect the distributor vacuum advance and cap the vacuum line. Set the ignition base timing. Reconnect the distributor vacuum advance. Work back-and-forth between idle RPM and idle mixture until the engine idles smoothest at the specified idle RPM.
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Db Thank you!!
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When checking base timing, set the idle down as low as possible to ensure you aren't getting any mechanical advance. After verifying base timing, rev it up to see how fast the mechanical comes in and how high it goes. Most stock SBCs run well with about 8-12 degrees base timing, and they might take even more. The mechanical usually adds 18-20 degrees.
Bruce