mopar 3 B
Well-Known Member
Avgas of today isn't what it used to be either. Better start building practical street engines and have it over with. We all have known for a long time the day would come.
Fuel used for High Performance 440
- Thread starter Davison
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Try this web site
www. sunocoracefuels.com/fuels Both leaded and un-leaded various octane ratings..available in 5 gal cans.
for a local supplier in your area or try an get 101 LL (low lead) AV gas .....it works great but expensive....maybe $ 6.00 - $7.00 gallon
BOB RENTON
mopar 3 B
Well-Known Member
Still would be cheap has by Cal rates. Premium in part of Arizona is close to $5.00.
Rebelrouser
Well-Known Member
Where I live 91 octane non alcohol fuel is best we have at the pump. And that is what I use in my street cars, mainly because it is more stable when they sit and no corrosion or water issues from the alcohol. Issues you should be concered about as mentioned are spark knock and valve recession. Valve recession will be worse if you take long trips, short trips to a car show etc, not so much, but want to do the hot rod power tour then worry.
On the spark knock adjusting the advance curve in the distributor is more important than running a high octane fuel. Kncok is more of an issue at midrange speeds and loads than at wide open throttle. I use a performance trend engine program to generate a proper advance curve and then set up the distributor to match that curve, it seems to work well. Usually you are limiting the advance a slower engine speeds
On the spark knock adjusting the advance curve in the distributor is more important than running a high octane fuel. Kncok is more of an issue at midrange speeds and loads than at wide open throttle. I use a performance trend engine program to generate a proper advance curve and then set up the distributor to match that curve, it seems to work well. Usually you are limiting the advance a slower engine speeds
Davison
Well-Known Member
I bought my 1972 Road Runner GTX in 1993 and have used Sunoco unleaded ethanol free 90 octane. 31 years later there are no problems with the engine and it runs like new. The 440-4 has low compression so I don't worry about a higher octane rating. My owners manual says to use the leaded fuel every 4th fill up only if the car is used to tow, mostly highway driving or high performance events. I don't tow, city/highway is probably 70/30% and although I do put my foot into it, i don't take it to the drag strip. So for me the Sunoco has worked well.
Slipping727
Member
I run two thirds recreational fuel, non- ethynol, with one third leaded race fuel in my 440 which is mostly stock. Works fine. A little pricey but it's not an everyday driver.
My biggest concern is staying away from ethynol fuel. If running pump gas, I would definitely add something to protect the fuel system from water/ethynol damage.
My biggest concern is staying away from ethynol fuel. If running pump gas, I would definitely add something to protect the fuel system from water/ethynol damage.
not so famous bob
Well-Known Member
I had 2 hemi`s back in the day , raced one , and drove the other to work when I could afford it .
They would not run w/o pinging on anything but 100 octane or better in most cases , av gas worked , but could not delete it any at all .
Has gas changed that much now , I run my 505 wedge on 93 non eth. , with about the same timing and comp. , and it doesn`t ping at all...
Davison
Well-Known Member
Some added information that might be helpful in your decision. The leaded fuels back in the day had 2 grams of lead per gallon. When I was making my decision on what fuel to use I called up VP Racing Fuels since they have a leaded station near to me. They said that their leaded VP110 had 4.0 grams of lead per gallon so double of what was needed when our cars were engineered. It is also non-ethanol. So to get close to the fuel of the 1960's and 70's you would need a 50/50% mix. If you wanted to run the Chrysler recommendation for the 1972 440-4, then you would only need 0.5 grams of lead per gallon. So for every eight gallons one would need to be leaded. I think the gas tank on the '72 is about 20 gallons so for a full tank, about 2-1/2 gallons would be leaded. If its all ethanol free then you pretty much come close to the fuel back then.
Either 91 non-ethanol or 93 ethanol should be fine. I have a habit of never filling my tank more than 1/2 full which means I put fuel in it often enough even with sparse driving, to avoid having fuel go bad. My garage is dry and well insulated so I don’t worry about condensation forming in the tank. One caveat, it may just be my old 440 but it doesn’t tolerate the somewhat universally used max total timing target of 36 degrees on pump fuel - it would ping. I reduced the amount of mechanical advance so that I could increase the base timing to 16-17 degrees and keep max at 34 degrees and it runs great on that.
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