In good ole New York, a car wash called Delta Sonic carries 100 octane in the pump...about 2.50 somethin a gallon...but it is readily available

Kyle

I too tried the so-called octane booster. It only reduced the pinging initially and completely fouled a set of plugs by the 3rd tank of gas.

There has been some debate on this forum as to whether or not octane booster actually boosts octane; personally, it is my belief that it only coats your combustion chamber to curb pinging and does not actually boost octane.

I admit to being confused by the whole octane issue. I've used 87, 89 and 93 octane in my slightly tweaked '78 L82 and found no difference in how the car performs. It runs great regardless.

I have only used Shell 93 octane in my '69 427/435 roadster and it also runs great. I haven't noticed any detonation at all.

Everything now is unleaded, and all lead did before was act as a valve lubricant and was an easy and cheap way of raising octane. There was always two ways of measuring octane...method and research. It used to be the higher of the two which gas suppliers advertised and what car manufacturers based their recommendations on. Now pump gas is based on the research and method octane ratings averaged together. It would seem likely that a current 93 octane or 94 octane rating might be the equivalent of 98 or 99 octane of past days, but that's only a surmise on my part. The additive packages that the different companies put in the fuels can make for much of the problems members report. Additive packages change in different areas of the country as well, and during different times of year as well. I know during winter months, auto fuels are made to be more volatile than summer fuels for starting in cold weather.

I know octane rating is a measure of resistance to detonation, and computer controlled systems can retard the timing when they detect detonation. I have a Lincoln LS with a 10.5 to 1 compression ratio, and it uses premium fuel and has no problems at all with detonation, due to it's computer system.

Since my '69 427/435 is happy on Shell 93 octane, I'll continue to use it. If anyone has detonation problems with individual cars, they should try different brands of fuel and see if any run better than others and stick with that brand. That would likely do better for most than additives and exotic fuels and blends.

I have heard that using mothballs will boost octane. Also, using transmission fluid in your gas will help as a cleaner. I dont intend on doing either of these, but hearing other people talk about doing it makes me a little sick to my stomach.

YEP!! That's why I have a '71 LS6, 9:0 to 1 compression from the factory and 425 hp. It runs on our crappy 91 premium here in California just fine. I've stuck higher racing fuel in it occasionally to keep the lead additive in the exhaust valve area.

Here in Michigan some stations sell Turbo Blue racing fuel 110 oct. $3.59 gal. My 355 in the 68 is 10.25 to 1 and runs good on 93 oct better on 100LL av gas and great on 110 Turbo Blue.

Hey Gunslinger,

Do you still have the stock compression ratio in your L71? Has it ever been rebuilt?

Also, do you know how many degrees of timing you're running at 3,000 rpms?

Just curious.

My L71 was rebuilt by the previous owner last year. He owns his own Chevrolet/GM dealership, and this car was one of his personal cars and decided to sell me this one.

He provided documentation and receipts for the motor rebuild. It was bored .030" over and installed new Wiseco pistons and a Crane cam kit ground to L88 specs. The heads were also milled .007", and the three carburetors were sent to Holley Custom for rebuilding.

The paperwork doesn't show what the compression ratio is now, but believe me, the car does run good, though a bit cranky when cold for a few minutes. With 4.11 gears, it can turn the tires blue in all four gears. In the Wiseco catalog, the pistons are rated for stock compression. I haven't checked the timing as the car runs so good and strong, it simply hasn't been an issue.

I'm betting your compression was lowered from the original 11:1 that I'm still running. That's probably why you're not having any problems. As for being strong, a lower compression 427 will easily out-muscle a high performance 350. Consider yourself lucky to have a previous owner that knew what he was doing, mine had a lot of ideals but not a lot of knowledge.

I live in St Paul area...and there are a few places here that sell 110 racing...they charge an arm and a leg tho $3.99/gal+...I also started using avgas..and that works great too...its about $2.19/gal around here. Dependingon how much you use the car...some folks tell me that they buy a 55 gal drum and fill it...thats good for the summer...but the thought of haveing 55 gal of gas in my garage doesnt excite me....also...there is a fellow that sells a legitamte "octane booster". It's not in the stores, but i saw it at Bllomington...and I'm told that it works quite well.