Hey guys whats up. I have had 7 stangs before this one I just picked up today. Heres the stats of the car: 1990 mustang clean motor was rebuilt about a year ago pistons,rods,bearings,bored30 over,cam,lifters,stahl converter, and has offroad h and flows. Anyway, what I need to know is, will it hurt the car if I accidently put 87 octane in it? He called AFTER i put the gas in and said "hey did you put premium in" i told him no and he said it should be fine, and just to put octane booster in it. Then I got talking to my other freind and he said NOT to run it hard until I get the 87 octane out of there otherwise I could have problems. Do I have anything to worry about here?