What is the timing degree on a SBC 350?

On a Chevy small-block 350, timing isn’t a single fixed number. For most stock setups, ignition timing targets are typically around 6–12 degrees BTDC for the initial timing and roughly 32–36 degrees BTDC for the total timing at cruise RPM, with cam timing set according to the cam card. Exact values vary by compression, cam choice, and distributor type, so always verify against factory or cam-spec data for your engine.

Ignition timing vs cam timing: what "timing degree" means

To understand the question, it helps to distinguish ignition timing (spark timing) from cam timing (valve timing). Ignition timing is when the spark plug fires relative to the piston’s position on the crankshaft, usually measured in degrees before top dead center (BTDC). Cam timing refers to how the camshaft’s lobes rotate relative to the crank, set by the timing chain/belt and cam gear marks and specified by the cam manufacturer.

Ignition timing basics

For a typical stock SBC 350 with a conventional distributor and carburetor or throttle-body injection, the common targets are:

• Initial timing (idle, BTDC): roughly 6–12 degrees


• Total timing (all mechanical advance, at about 3,000 rpm): roughly 32–36 degrees BTDC


• Vacuum advance: adds some extra timing at light load/cruise when enabled by the distributor and vacuum source


• Performance or high-compression setups may run a little more total timing (often up to about 34–38 degrees BTDC) while watching for ping under load

These ranges assume a healthy engine with a proper timing chain, distributor, and ignition system. Always verify against your cam card and factory service data for your exact year/model.

How to check and adjust ignition timing on a SBC 350

The following steps outline a typical process to verify and set ignition timing on a small-block Chevy 350. Doing it carefully helps prevent detonation and engine damage.

• Warm the engine to normal operating temperature and bring the idle to the recommended speed (often around 650–850 rpm)


• Disconnect the vacuum advance line from the distributor (or cap the port) to measure base timing without vacuum influence


• Connect a timing light to the No. 1 spark plug wire and aim the gun at the timing tab on the front of the engine


• With the vacuum line disconnected, rotate the distributor with a wrench so the timing mark lines up with the desired initial timing (BTDC) on the timing tab (commonly 6–12 degrees)


• Reconnect the vacuum line and recheck idle timing; ensure the engine runs smoothly and does not ping with the vacuum advance engaged


• Increase engine speed to about 3,000 rpm and observe the total timing (the timing mark should indicate the specified total timing). If necessary, rotate the distributor to bring the total into the recommended 32–36 degrees BTDC range


• Take the car for a test drive and listen for any pinging under load; adjust within the recommended range as needed

Following these steps will help you set a safe and efficient ignition timing for a typical SBC 350. If you have a performance cam, aftermarket distributor, or higher compression, consult the cam card and ignition-timing recommendations from the manufacturer or a qualified technician.

Cam timing specifics for a SBC 350 (installing a cam)

Cam timing—the relationship between the crank and cam when installing or replacing a camshaft—depends on the specific cam you’re using. The cam card from the manufacturer typically specifies the installed centerline, exhaust/ intake timing events, and any required offsets. Many Chevy SBC cams aim for an installed centerline in the neighborhood of 110–114 degrees, but values vary widely by profile. Always follow the cam card and, if needed, verify with a dial indicator and timing marks on the timing chain/gears after installation.

When you change the cam, you may also need to recheck ignition timing, since valve timing can affect engine torque and knock resistance. If you’re unsure, seek help from a professional to ensure both cam timing and ignition timing are set correctly for your configuration.

Summary

“Timing degree” on a SBC 350 can refer to ignition timing or cam timing. For a typical stock setup, ignition timing targets are roughly 6–12 degrees BTDC initial and about 32–36 degrees BTDC total at cruising RPM, with vacuum advance contributing to the total at light loads. Cam timing is cam-specific and must be set per the cam card or manufacturer’s instructions. Always verify exact figures for your engine, use a timing light for checks, and test under load to avoid pinging and detonation. A properly timed SBC 350 delivers reliable performance and efficient fuel use across its operating range.

Will an engine run if timing is 180 degrees off?

No, an engine will not run if the timing is 180 degrees off because the ignition and valve events will be completely out of sync with the piston's position, firing on the exhaust stroke instead of the compression stroke. At best, it may sputter or pop, but it will not start or run properly. This error means the spark plug will fire while the cylinder is full of exhaust gas, and the valves will be open at the wrong time, making combustion impossible. 
You can also check out this video:1mErik StrawnYouTube · Oct 6, 2020
Why a 180-degree timing error prevents an engine from running

• Incorrect stroke: With the timing 180 degrees off, the spark plug fires during the exhaust stroke, not the compression stroke. This is because the piston is at the top, but the air-fuel mixture is not there to be ignited—it's full of exhaust gases ready to be pushed out. 
• No combustion: For an engine to run, the spark plug must fire at the very end of the compression stroke to ignite the compressed air-fuel mixture, creating an explosion that forces the piston down. A 180-degree error makes this impossible. 
• Incorrect valve timing: A 180-degree error in valve timing is also a major problem. It means the intake and exhaust valves will be operating in the wrong sequence relative to the piston, preventing the engine from breathing correctly. 
• Symptoms: If an engine with this issue is cranked, you will likely hear popping and backfiring from the exhaust, but it will not start and run. 

You can also check out this video:58sAuto Repair GuysYouTube · Feb 14, 2019
Common causes of a 180-degree timing error

• Distributor installation: A common mistake is incorrectly installing the distributor. If the engine was rotated to Top Dead Center (TDC) on the compression stroke, the distributor should be installed to match the correct firing order. If the distributor is installed 180 degrees out, it will send the spark at the wrong time. 
• Timing belt or chain jump: A significant jump in the timing belt or chain can throw off the synchronization between the crankshaft and the camshaft by 180 degrees. 

You can also check out this video:52s8020 AutomotiveYouTube · Oct 6, 2024

What degree should ignition timing be?

Idle/staging is typically 55 degrees to ignite the cylinders with a rich idle mixture. Launch typically 50-53 degrees adjusted for an optimum power at launch. Sudden drop of the timing to typically 36 degrees, approx. 1 second into the run, to instantaneously reduce power for reduced traction from tire growth.

What should SBC 350 timing be set at?

For an SBC 350, a typical initial timing is 8-12 degrees BTDC, which you set at idle with a timing light while the engine is warm and the vacuum advance is disconnected and plugged. Total timing should be set at higher RPM (e.g., 36 degrees BTDC at around 2500-3000 RPM), where the mechanical and vacuum advance are both fully engaged. Adjusting the distributor's position while the engine is running is the method for setting the timing.
 
Setting initial timing

1. Warm the engine to operating temperature. 
2. Disconnect and plug the vacuum advance hose from the distributor and carburetor. 
3. Locate the timing marks on the harmonic balancer and pointer, and use a timing light to find the correct initial timing mark (e.g., 8 degrees BTDC). 
4. Loosen the distributor hold-down bolt just enough to allow the distributor to be turned by hand. 
5. Use the timing light to flash the timing mark and observe the alignment. 
6. Rotate the distributor until the timing mark aligns with the desired degree mark on the pointer. 
7. Once aligned, tighten the distributor hold-down bolt, making sure it is secure. 
8. Double-check the timing with the timing light to ensure it hasn't shifted when the bolt was tightened. 

Setting total timing

1. Disconnect the vacuum advance and plug the hose. 
2. Set the timing light to the desired total advance setting (e.g., 36 degrees BTDC). 
3. Start the engine and rev it to the RPM where the mechanical and vacuum advance are fully engaged (e.g., 2500-3000 RPM). 
4. Use the timing light to check the timing mark on the harmonic balancer. It should align with the setting on your timing light. 
5. If it is not aligned, you can adjust the mechanical advance by adding or removing shims from the distributor's weights or by adjusting the springs. 

Tips for timing

• Always use a timing light to accurately set the timing. Don't rely on feel alone. 
• The initial timing is crucial for starting, while total timing is crucial for performance. 
• If you have a performance cam, you may need to set the timing to a higher initial timing setting (e.g., 14 degrees) to get the engine to idle smoothly. 
• If your engine has a lot of mechanical advance, you can use a timing curve kit to adjust the timing more precisely. 

What is the timing degree on a small block Chevy?

For an SBC, the ideal timing is 34–36 degrees total advance for many performance street builds, while a stock engine might start with 8–10 degrees initial (idle) timing. The exact settings depend on your specific engine's components like the cam, heads, and compression ratio. Initial timing is set at idle, while total timing is the final advance achieved at around 2,500–3,000 RPM, and you'll need to disconnect the vacuum advance when setting both.
 
This video demonstrates how to set the initial and total timing on a small-block Chevy: 1mJackstand LegendYouTube · Jun 12, 2022
Initial timing

• What it is: The ignition timing at idle, which is the base setting that establishes how the engine runs before the centrifugal advance kicks in. 
• 8–10 degrees before top dead center (BTDC) Typical range: for a stock engine, or higher (e.g., 12–15 degrees) for engines with performance cams. 
• How to set:
  1. Disconnect and cap the vacuum advance hose. 
  2. Start the engine and let it reach operating temperature. 
  3. Use a timing light to find your desired initial timing mark on the harmonic balancer and pointer. 
  4. Loosen the distributor clamp and rotate the distributor body to align the marks. 
  5. Tighten the distributor and reconnect the vacuum hose. 

You can watch this video to learn how to set the timing on a small block Chevy, including connecting the timing light: 1mShiny Fast & LoudYouTube · Aug 22, 2022
Total timing

• What it is: The sum of the initial and mechanical advance when the centrifugal advance is fully engaged. 
• 34–36 degrees BTDC: Typical range: for many performance street engines. 
• How to set:
  1. With the vacuum advance still disconnected, run the engine up to approximately 2,500–3,000 RPM. 
  2. Use the timing light to find the total timing mark. It should align with your target (e.g., 36 degrees). 
  3. If the timing is not at the correct degree, you may need to adjust the distributor's mechanical advance by changing the springs or weights inside the distributor, or by adjusting the initial timing. 

Why timing varies

• The ideal timing is not a one-size-fits-all number and is affected by other engine components. 
• Camshaft: More aggressive cams can require more initial timing to run efficiently. 
• Heads and compression: Cylinder heads and compression ratio impact the burn rate and can require more or less timing. 
• Vacuum advance: This provides additional timing at part throttle for better driveability and fuel economy, and is set separately from the initial and total timing. 

This video explains the importance of total advance timing and how to adjust it for optimal engine performance: 1mCorvetteHopYouTube · Oct 27, 2013