Fuel mix

[Cesar L.]

I have a L79 67 Corvette with transistor ignition that I want to reset the timing to factory specs. I've heard that I need to mix some high octaine with today's premium fuel. Can anyone help me out on a good fuel mixture.

Best Regards,
Cesar

[Duke W.]

Re: Fuel mix

It's not likely that you will need to use anything other than unleaded premium.

The initial timing should be set in the range of 4-10 degrees. The total centrifugal is 30 so in the 4-10 initial range, total WOT timing is 34-40. If it detonates at 10, drop it to whatever is required to quell any detonation.

If this car is a fairly new acquisition, you should check whether the spark advance map has been modified.

There are a number of variables in the detonation equation - ambient temperature, altitude, locally available fuel octane to name a few. Most Corvette engines that are still in OE spec, including the spark advance map, will operate on today's unleaded premiums with maybe just a slight reduction in initial timing.

The RON spec for most high compression vintage Corvette engines is 99-100 and 93 PON is equivalent to 97-98 RON, so it's not that far behind vintage leaded premiums.

Duke

[Duke W.]

Re: Fuel mix

It's not likely that you will need to use anything other than unleaded premium.

The initial timing should be set in the range of 4-10 degrees. The total centrifugal is 30 so in the 4-10 initial range, total WOT timing is 34-40. If it detonates at 10, drop it to whatever is required to quell any detonation.

If this car is a fairly new acquisition, you should check whether the spark advance map has been modified.

There are a number of variables in the detonation equation - ambient temperature, altitude, locally available fuel octane to name a few. Most Corvette engines that are still in OE spec, including the spark advance map, will operate on today's unleaded premiums with maybe just a slight reduction in initial timing.

The RON spec for most high compression vintage Corvette engines is 99-100 and 93 PON is equivalent to 97-98 RON, so it's not that far behind vintage leaded premiums.

Duke

[Cesar L.]

Re: Fuel mix

The information posted will be very helpful.
Thanks,
Cesar

[Cesar L.]

Re: Fuel mix

The information posted will be very helpful.
Thanks,
Cesar