Wich Gas...?

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Elgrano, Apr 8, 2006.

  1. Hi Guys...
    I am not new to Mustangs but I am going to get my first classic 67' in two weeks...It might sound dumb but...which gas should I use? (stock engine)

  2. Good 'ol 87 is just fine :D I'm running 10:1 compression with iron heads and I can run 87 octane with no problems.
  3. I use 87 or 89 (around here, 89 is cheaper than 87). There's a bottle of lead additive still in the trunk from the previous owner, but I haven't used it since I got the car.

  4. well i may get flamed but i run the highest at a gas place. i run mid grade in my 88 s10 4 banger cause it seems to run better (no valve noise)
  5. same here. A local Mustang shop recommended to run the highest octane you can (91 for me), for the gas it was designed for back in the 60s was something like 93 octane. Although I do sometimes fill up with the 87, and notice no difference :shrug:
  6. I run 87, but have experimented with mid and premium grades....have not noticed any difference
  7. use the lowest octane fuel that you can. if you can use 87, great. dont spend any more money on gas than you have to.
  8. ^^ Actually, thats very accurate. You will get the best performance by running the lowest octane that your engine and tune can tolerate without detonating. You can actually lose power by using a higher octane fuel, which is simply more "stable", meaning that it is harder to get to combust, which can cause you a little (probably not noticable) power.