Hi, I have a 1986 Pontiac Parisienne with a 4.3 V8. And I use 89 Octane from Amoco (Amoco Silver) Should I use 87 ( Amoco Regular) or 93 Octane ( Amoco Ultimate) Instead?
Thanks;)

If your car runs good on silver I'd stick with it, the key is smooth pickup without the engine knocking.