Best Gas for Your Classic Car: How to Fuel an Old Chevy or Olds

When it comes to maintaining your classic car, particularly vehicles like your 1969 Chevy and 1971 Olds, the choice of fuel can greatly impact their performance and longevity. In this article, we'll explore the best gas options for older cars, focusing on the benefits of using high-octane non-ethanol fuel and how to handle ethanol-laden alternatives.

Understanding the Needs of Your Classic Car

Your automobiles are designed to run on high-octane fuel due to their supercharged engines. For a normal older car, it's important to choose a fuel based on the manufacturer's recommendations. If the manual specifies a minimum octane level, it's wise to choose fuel that meets or exceeds this requirement. For example, if the manual recommends 97 octane, you might opt for 98 octane or even 100 octane if available.

For sluggishly available high-octane fuels, you can add a lead replacement additive that serves as a mild octane booster. This helps ensure the fuel's performance, even if it falls slightly below the recommended octane level.

High Octane Fuel: A Must for Older Classics

High octane non-ethanol fuel is crucial for older classic cars, especially those with higher compression ratios. This type of fuel helps prevent engine knocking or pinging, which can lead to damage such as cracked piston rings. Excessive pinging can cause serious issues that can compromise the engine's performance and longevity.

For enthusiasts who have access to Gulf No. 97, this brand has a rich history of being a high-compression engine fuel favorite. Gulf No. 97 offered up to 115 octane, which was perfect for old school high-compression engines. Although this fuel is no longer available, enthusiasts can still achieve similar results by using premium gasoline options and lead replacement additives.

Navigating the Challenges of Ethanol Fuel

While high-octane non-ethanol fuel is ideal, many areas lack this option, making it less accessible to classic car owners. Ethanol-laden fuels, like E5 and E10, are more readily available, but they present unique challenges. Ethanol can deteriorate older fuel systems, particularly carburetors and fuel lines, leading to issues such as clogged jets and damage to seals and hoses.

For classic cars, especially those with older fuel systems, it's advisable to stick to low-ethanol blends, like E5. If you insist on using E10 or E85, ensure your vehicle's fuel system is compatible with alcohol-based fuels. If you're unsure about your car's compatibility, it's best to consult with a professional or use ethanol-free fuel.

Ensuring Compatibility and Restoration

Some classic cars may require modifications to their fuel systems to handle unleaded fuel. Older engines designed for leaded fuel, which used the lead component to improve octane ratings and lubricate valve seats, may develop issues if run on unleaded fuel. For such cars, you can opt to:

Replace original valve seats with hardened ones during a major engine rebuild. Add liquid additives that provide similar functionality to the leaded fuel.

If you're unsure about your car's compatibility with unleaded fuel, consulting a professional mechanic or using a fuel additive designed for classic vehicles can help ensure smooth operation.

Conclusion

Selecting the right fuel is a critical aspect of maintaining your classic car. High octane non-ethanol fuel is recommended for older classics with high compression ratios to prevent engine pinging and damage. For those living in areas with limited access to pure non-ethanol fuel, ensuring compatibility with ethanol blends or using lead replacement additives can help mitigate issues. By understanding the needs of your classic car and making informed choices, you can keep your older Chevy or Olds running in top condition for years to come.