Big Blue 65

What do people recommend for a 455 Rocket? Regular or premium. Thanks to everyone that is answering all my newbie questions about my new ride that I've always wanted since I was a kid but don't know much about!

oldcutlass

I would suggest the highest available octane you can get in your area.

Fun71

Too many variables and not enough information to answer the question.
Depends upon the year, if it's been rebuilt or not, and the ambient temperatures.
A factory 71-76 8.5:1 engine would probably run fine on low octane fuel during cool/cold weather.
An early factory 10.25:1 compression or rebuilt high compression engine running in Phoenix 110+ temps during the summer would likely need as high octane fuel as you could find.

Big Blue 65

Mine is a completely stock all original 1968 Olds 98 with Rocket 455

Professur

Not relevant to your motor, but I've been running 91 in my 307 all winter to get away from the corn ****. Costs a little more, but I've run the numbers and I am getting better mileage, enough to offset the cost and more. Most if not all 91+ fuels don't have any ethanol added. As with all things, just my observation. Your mileage may vary.

oldcutlass

All fuels in my area have ethanol added. I believe your engine has a compression pressure of 180-190 lbs, it needs higher octane than regular.

Sugar Bear

A 1968 all original 455 4 barrel is a high compression motor. I would ONLY run it on premium and still be on the alert for detonation/pinging. Some of the original fuel caps had a red decal on them stating premium fuel only as did some of the air cleaner decals.

Think about replacing the timing chain and gears as maintenance if it has not been done already. The plastic from the old cam gear breaks off and can clog/restrict the oil pump intake or the chain can jump on the worn cam gear without warning and cause other engine damage.