EngineerJay

What type of fuel should be used for a 1971 vette? Should a lead additive be used?

zwede

'71 was the first year that was designed for regular unleaded. Although you may want to stick to mid-grade to be safe. No lead additive should be used.

If you have a hi-perf version (LT-1), use premium unleaded.

Rowdy Rat

Not entirely true.

While the compression ratios were lowered to prepare for the use of lower octane fuels, the induction hardened valve seats for use with unleaded fuels didn't come along until 1973 if I remember correctly.

Still, unless you plan to use the car in continuous high load or high rpm operation (i.e., hours at a time), you really don't have to worry too much about valve seat recession. For the manner in which most of us use these cars, unleaded fuel will work just fine.

Agreed... A mid range (91 octane or so) unleaded fuel should work just fine.

Regards,

Stan Falenski

zwede

Just checked my '71 owner's manual and here's what it says:

"All 1971 General Motors cars including your Corvette are designed to operate on unleaded or low-lead (zero to 0.5 grams per gallon) gasolines. However, any gasoline with 91 Research Octane Number or higher will satisfy your engine's octane requirements. Use of unleaded or low-lead gasoline will keep your engine running efficiently and play an important part in reducing exhaust emissions of hydrocarbons and particulates"

Note that they say 91 octane RON. Today gas is rated as the average of RON & MON. The RON number is higher. So that means 91 RON in 1971 is regular gas today.

7T1vette

My 1971 'base' engine SB runs just fine on regular pump gas. I have the distributor curved for 36* mech advance at 2800rpm and no pinging at all when at WOT. If you have one of the "hi perf" engines (kind of an oxymoron, in 1971), you may need the mid-grade of fuel; but I don't think you would need premium to run well. Since you have aluminum heads, you can get away with a little higher compression (than with iron heads) and still not have pre-ignition problems.

capevettes

It would be helpful if you told us what motor is in your car. Basically, whatever octane the car requires to prevent detonation (assuming it's set up correctly) is what you should use. Lead in not needed.

Mike Ward

Exactly. 91 RON is equivalent to 87 AKI which is today's 'regular' gas.

Just think of the hundreds of millions of gallons of 'premium' gas plus octane boosters plus lead additives that have been put through these cars over the years. What a waste

EngineerJay

If the former owner used lead additive would I have to continue that?

It's the 71 base engine.

zwede

Nope, the engine has no "memory".

Mike Ward

It never needed the lead in the first place, so the sooner you stop wasting money the better.