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Discussion Starter · #1 ·
So I’m currently running a rebuilt 400 small block with a mild cam, fast fuel 600 carburetor with a stall converter & 350 turbo trans. But not sure of engine rebuilt specifics exactly being my first oldschool carbureted car.
The Question is? What’s the Pros & Cons of running 90 rec fuel vs. Regular unleaded?
Main issue being the only station in town with the 90 is outta my way, plus the cost difference! Also occasionally still having a stalling out issue, wondering if the gas could be the cause?
Any suggestions? Any advice Pls & thx.
 

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I run Ethanol free 91 in mine and it's night and day compared to that regular crap, all around runs so much better and better mileage, only draw back is availability not every station carries it.
 

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Discussion Starter · #3 ·
I run Ethanol free 91 in mine and it's night and day compared to that regular crap, all around runs so much better and better mileage, only draw back is availability not every station carries it.
Gas mileage is another question, seems ta be burning a tank a week! At $4 bucks a gallon compared ta $3 dollars is tempting to switch.
 

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Sure it is, with good gas you can tune it up right and get better flame, only time it's a waste is if you had super low compression, higher octane needs more compression. You can run regular unleaded if you need to, only thing is you gotta watch for detonation, if it rattles you have to back off timing then it runs like crap and there goes performance and mileage, the ethanol premium has better octane but still not as good as the ethanol free, I had to use it and it works but performance and mileage suffers, not to mention the ethanol stuff destroys everything.
 

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So I’m currently running a rebuilt 400 small block with a mild cam, fast fuel 600 carburetor with a stall converter & 350 turbo trans. But not sure of engine rebuilt specifics exactly being my first oldschool carbureted car.
The Question is? What’s the Pros & Cons of running 90 rec fuel vs. Regular unleaded?
Main issue being the only station in town with the 90 is outta my way, plus the cost difference! Also occasionally still having a stalling out issue, wondering if the gas could be the cause?
Any suggestions? Any advice Pls & thx.
Did you ever fix your engine issues?
Sounds to me like there's something wacky with the carb, but curious to see what it was.
 

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...or the fuel was boiling in the carburetor.

A stuck-closed heat riser valve, or a restricted side on a dual exhaust can cause excessive heating of the manifold exhaust gas crossover, which then cooks the carb.
 
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