89GTRed

usually 89 with 14* timing

red50stang

If your all stock, running 87 is your best bet it's what the manufacturer recommended, so it is perfectly safe for your car. The best you can hope for using 93 as opposed to 87 is probably just better gas mileage, I run 93 in my lightning and my mustang and I get better gas mileage and it feels a little different but mine is modded, my lightning has to run 93 or it idles really rough. So I say for stock save your money and run 87, but if you haven't tried 93 then try it and decide for yourself.

alec3369

ok thanks everyone

PX429

Like he said, It's in your manuel. So you shouldn't run anything higher then that. It may even make you slower if your run 93 on a stock setup. You will need to advance your timing in order to run at 93 and actually gain power.

luckythirteen13

91, but im supercharged

5.0_faithful

I use 87 and run at 10* and 12* timing with no problems at all. I have been running it at 10* timing to experiment with gas mileage and I just got 19.9 mpg on my last tank. I have averaged 18.5, 18.3, 18.6 & 19.9 so my mods are working well I think!!!!!!!!! Oh let me add in that is all city mileage !!!!!!!!