[reldridge]

I think the key here for oldeguys sake, and anybody else that isn't boosted or all-motor high revving machine is to go with what the manfacturer recommends. If Ford says 87 is good, and they have tuned the ECU, injectors, etc. for 87, why run higher octane, except for in high load applications (towing, track day, etc.)?

Especially now, when most cars have knock sensors built in to pull timing if the engine starts to detonate (ping), what is the point in running higher octane fuel day to day, if your engine is tuned for regular?

I'm actually asking, if anybody has concrete proof that if I run 91 in my 87 tuned car that things will be better, then by all means!