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I have a 1966 Mustang coupe, 2 barrel 289, and was wondering if there would be any benefit in using the higher, and more costly, octane gas. Currently, I am putting the highest grade gas into the car, mostly because I think that it will keep the valves and cylinders cleaner. But, recently I began to think that these higher octane gas didn't exist in 1966 and maybe I might be doing more HARM then GOOD.
What is the opinion of the experts here on the forum. Thanks.
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You're not doing any harm, you may or may not be doing any good. Use the lowest grade of gasoline that does NOT cause your engine to ping, or pre-detonate.
If under moderate to high load there is no pinging, you're all good.
BTW, octane ratings were different when these cars were new, I'm not sure if there is a direct correlation. Also, lead was added in the old days.
The rating today is much different today versus then.
The 1966 owner’s manual states that a 2V 289 requires 94 minimum octane back then. The 4V and HIPO required 100 or better.
Like Axeman says use what works best in your car.
BTW higher octane doesn’t necessarily mean the "best" gas. Depends on the additives the maker adds when refining.
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Nightmist Blue 1966 Coupe.
289 A code. Holley 600. Edelbrock dual-plane Intake. TRI-Y headers & Glass packs. C-4 B&M Shift Kit, Kevlar Bands. Billet Servo. PowerTraX Auto Locker. 1 1/8" front 1" rear ADCO sway bars. KYB Gas-Adjust Shocks. Export brace and M/C bar. CSRP KH Disc Brake Conversion. Torq Thrust D's w/ B.F.G TA Radials.
Don't know about the nitrogen enriched gas, but a friend of mine who drag races once dyno tested different makes of pump gas in his 1000hp car, He found that Pioneer was giving him the best and most consistent response, but all the others were close behind. Unless hundredths of a second matter to you, it doesn't really matter which brand.
Vehicle: 1969 Mustang Grande (modified) Winter Blue Metallic
Location: Santa Monica, Calif.
Posts: 901
The correct answer:
Quote:
Originally Posted by TexasAxMan
...Use the lowest grade of gasoline that does NOT cause your engine to ping, or pre-detonate.
I run 87 in my 302 and it's really smooth. Gasoline is different from state to state with some states like CA requiring "cleaning" additives. Some discount gas vendors like Pioneer and Arco might not offer the same quality as the big boys like Exxon and Unocal. There's no one answer for all cars.
I've had 4 Vintage Mustangs over the years, 2- 200 C.I.6 cylinder cars, and 2- 289 V8 (1 2bbl, 1 4bbl). All of them ran just fine using regular unleaded gas. Never had any problems using regular.
Hope thet helps.
Jay
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What Octane Gas for '66 Mustang
