What type of gas should I be using?
 

I purchased a 65 mustang witha new 289. The previous owner was using 94 octane gasoline. This doesn't sound right to me. Any suggestions as to what type of fuel I should be using?

I have a 65' with the original engine, I use the highest octane I can find, as if I look in the book it tells me to use a minimum of 90 octane I think it was...

using 94 sounds good to me

Stock or not?
 

Is this a bone stock '65? They were made (I think all engines except the 271 Hipo) to use leaded regular at about 90+ octane. The 271 Hipo with 10.5/1 CR may have needed a little more (93?).

The leaded gas prevented exhaust valve intrusion into the head valve seat. Almost anyone who drives these cars much now uses hardened inserts for the valve seats in the heads so as to make them compatible with todays unleaded gas.

For my car, I use only Chevron Supreme 92 octane, but that's for a modified performance engine with about 9.5 CR. I may not even need that.

Rev

Thanks..I will continue doing what I'm doing. For winter storage I have added Stabil to stabilize the fuel. Is there anything else I need to be doing?

use only the octane you need to prevent detonation as any more than that is a waste of money.