Which gas to use.

Anyone have any thought as to which octane rating gasoline to use in a 72 454 with 8.5 CR??  87(Regular); 89( Plus) or 92/93 (Premium)??

Thanks

 

NJ BB Ken

windrider120038488.3294791667

Since the factory owner's manual is likely no help, about all you can do is tune the car to factory specs, then try the lowest octane gas and see if you get any pinging under load and normal driving. If you do, step up to the next higher octane and try again. When you get no pinging you've found the appropriate fuel blend.

That's what I did and found that my 74 454 is not happy under 93.

Oddly enough, you may find different brands will also run differently.  It come down to uses what works the best, and to a lesser degree, for the cheapest price.

Here we can only get 91 as the highest, I find by adding octane boosters
(off the shelf), it runs the best. Racing boosters will kick it up 7 points, a
clean ride in my set up (though an extra $7.50 a tank fill up)....

My 71-454 runs well with Sunoco 94. Never had any problems.

 

93 works great for my SB. Be careful about octane boosters. My friend down the street has a 63 small block and he was running octane boosters for about 3 years. Recently he pulled the engine apart to replace the cam and heads and there was a funny orange stain on all the exhaust parts and pitting on the pistons. He asked the engine guy what it was from and the only thing they could figure was the octane boost.

I've been running 93 octane. The car actually gets better mileage on premium, and I can really tell the difference in performance between premium and the mid-grade. The extra cost might be close to a break-even with the improved mileage.

The stains are from the octane boosters.  Not all of them do it, but it's not uncommon.  It's not a problem unless it leaves deposits. 

And yes sometimes the more expensive gas is cheaper due to improved mileage.  Also keep in mind pinging long term can damage the engine.  Another advantage of high test when needed.

[QUOTE=kstyer]

The stains are from the octane boosters.  Not all of
them do it, but it's not uncommon.  It's not a problem unless it leaves
deposits. 

And yes sometimes the more expensive gas is cheaper due to
improved mileage.  Also keep in mind pinging long term can damage the
engine.  Another advantage of high test when needed.

[/QUOTE]

Wow, I didn't know that. The guy who built my small block (at 10:1) said I
would be better off running boosters due to the high compression (and it
DOES run better with better milage), and I do stay away from the cheap
brands. Is constant octane boosting a bad practice or just with certain
setups?