* Specific engine configuration: The camshaft, carburetor (or fuel injection type), and other modifications will significantly alter the ideal timing. A stock engine will have different timing requirements than one with performance upgrades.
* Engine condition: Worn components can affect optimal timing.
* Fuel: The type of fuel used can influence the ignition timing.
Instead of a single number, you'll need to find the specifications in a few places:
1. Owner's Manual: Your Corvette's owner's manual should provide the recommended initial timing setting. This is the timing setting at idle.
2. Service Manual: A Chevrolet service manual for a 1980 Corvette with a 5.7L engine will be your best resource. It will specify the initial timing and the total timing advance (mechanical and vacuum advance combined). This manual will likely give you a range rather than one exact number.
3. Timing Tab: The distributor itself might have a timing tab indicating the initial timing setting from the factory. However, this might be inaccurate if the distributor has been replaced or altered.
General Guidance (Use with Caution): While a precise number is impossible without more information, a *rough* initial timing for a stock 1980 5.7L Chevy small-block might be in the range of 8 to 12 degrees BTDC (Before Top Dead Center). The total timing advance (at higher RPM) would be considerably more, possibly 30-36 degrees BTDC. This is just a broad estimate, and significantly deviating from the correct timing can damage your engine.
Crucial Note: You should not rely on these estimates. Always consult your owner's or a service manual. Using a timing light and following the procedure outlined in a reputable manual is essential for accurate timing adjustment. Improper timing can lead to poor performance, reduced fuel economy, and potential engine damage.
