better mileage with higher octane?

Some how I just can't see a circle track racer saying. "We can get along fine with less power." Even if some were to take that aproach in the interest of reliability, I am sure some would have opted for dual quads if they were allowed. There's no question they were a factory item. And there is still the matter of the Fords being allowed to run dual quads which were not stock.

Cheese Bob makes you think I am lying? You see, you guys have enormous egos and you think no one else could come up with the right answer except yourselves. When the Chinese launched their Space program you thought they bragged, and they did go into space, and many countries in Europe can do what you did. Insulting people won't get you any where.

Venus is posting as a fake Komin in other discussion groups .

Venus=B2=B2 wrote:

Well, that also begs the old question of whether a dual-quad *really* makes more power than a well-tuned big single on the same engine, too.

Depends on a lot of factors. And depends where you want the power. The single will likely give better throttle response, so make a better short track car (or roundy-round) where the dual quads will shine at full throttle high revs - like a floor-it-and-go dragster.

IMO circle track racers operate in a narrower rpm range than a dragster. And on tracks like Daytona the pedal stays planted most of the time, so response isn't a problem.

Another factor is that back when we were talking about they didn't have the huge carbs they did later. The dual-quads made more power because they provided the most veturi area.

Maybe you are looking at the US version of the 350 instead of the Canuck block?. This one was the real Olds engine before the Chev 350 narrow block ones became commonplace. My memory could be failing me but I just remember they backed the compression ratios down after that one. The trend was to increase compression more and more in the 60s.

It has worked for computers. And for those that persist they changed the box so nothing fits too.

I didn't insult you and cheese didn't make me think you were lying. Good luck with everything else..... wow

True at Daytona *today*, but I kinda doubt that they ran wide open through the turns back in the big-block engine, skinny tire, no aero downforce days of the 60s even at Daytona. I wish they still ran that way, the racing at Daytona and Talledega today is more boring than watching grass grow.

That's certainly true. The dual quads on the old cross-ram 413s were only good for about 400 to 500 CFM each at best.

What are these quads you talk of ?

Graham

I'm not a gearhead, but I doubt if even the most ambitious measure their engines in quadrillions of BTUs, so I guess they must be talking about four throat (barrel) carburators :)

An Olds Rocket is an Olds Rocket - not a Chevy The 350 OLDS engine came to the Cutlass in 1969. This was the 4.057" bore rocket, not the 4.00 inch bore Chevy and was used AT LEAST until

1985.1986 to 90 did not have a 350 engine available.The Chevy 350 was used in 1992 and up In Canada the 350 was not available (except the Deisel) from 1981 to 1985 and in 1979 the"L" code 350 was a Chevy while the "R" code was an Olds. This is from the information I have available (which covers USA and Canada.) In Metric speak, the olds was a 103mm bore, and the Chevy a 96.5 In 1979, the 103mm 350 was 7.9:1, and the 96.5 was 8.5:1

4-barrel carburetors. One under each of the red air-cleaners in this photo:

The Olds Rocket lived on into the early 1990s. It was the "5.0L" (about

307 CID) and "5.7L" (350 CID) engine used in the Cadillac Broughm (formerly "Fleetwood Broughm) up until the time that they started putting the Chebby LT-1 350 in the Broughm, the "bathtub" Caprice, and the Buick Roadmaster.

Absolutely could not be more WRONG here. I race(d) in a class that limited compression to 9.5:1. We could run any fuel we wanted, and time after time, people would put race gas (Sunoco 110 or Turbo 110) then have to crank their ignition timing way up only to come close to getting the same performance that they did using 92 octane pump gas.

I wondered but hadn't heard the term before.

Graham

That's hardly typical though. I thought we were talking about road cars ? Also modern cars don't have manual timing adjustment., the ECU does it.

Graham

His point was that if the engine was optimized for lower octane fuel then you have to resort to work arounds like bumping the timing way up with little if any bennefit. There are no absolutes but it has been my experience that the higher octane fuel has a slower flame speed for a given temperture/pressure. Increasing the compression ratio will increase the temp/pressure. Without the compression increase you resort to advancing the timing to get the temp/pressure back up where you need it. But that works against you because the engine has to overcome the rise in cylinder pressure before the piston gets to TDC. So even if the ECU advances the timing to take advantage of higher octane you get little if anything extra for your money. If you have a turbo you can crank the boost up and make more power, but that's not the same thing as mileage, which is what this thread is about.

Bruce