We were discussing octane earlier. Note the (R + M)/2 you see on pumps in U.S. This average of the RON & MON ratings is also called the PON rating referenced earlier where I stated:
In your 1964 Owner Manual on page 36 it indicates to use Minimum of 100 octane RON, or 89 octane MON. If you do the math to get the PON # that comes out to 94.5. So..that means the 93 Octane Premium in the US (PON) and the 99 Premium in the UK (RON) are both just tad lower than the recommended minimum octane for our 10.5 to 1 compression engines. My 64 CDV runs fine on 93 Octane, however, adding octane booster seems to give it more power. Keep in mind that the 94.5 would be a minimum recommendation and not an average or maximum recommendation.

Views: 238


You need to be a member of 63/64 Cadillac Website to add comments!

Join 63/64 Cadillac Website

Comment by Ryan Trask on September 13, 2012 at 1:50am

awesome thanks for this info! this might explain why my car runs a little rough sometimes, as i have been using 89 octane. ill switch it to 92 (since that's the highest i have in my area) and try a little booster

Comment by Jason Edge on September 2, 2012 at 9:22pm

I'm not sure how much lead additives raise the octane (if any). These higher compression engines were made for higher octane gas than the 80 something regular stuff they sell now. There is a lot of information on octane and engine compression out on the web. The best my car ever run (well before I rebuilt the engine) was on a strong dose of the 100+ octane AV Gas. I can remember here in NC growing up in the late 60's and early 70's where Hi Test was 95 to 98 octane and 93 would be more or less mid-grade.  The diffference was there were still many high compression engines on the road and being produced and the low compression 9.0 to 1, 8.5 to 1 and lower compression engines were just starting to replace these older high compression cars.  The new cars with low compression engines and electronic ignition that can automatically adjust timing as needed can burn the low octane stuff but I would never recommend putting regular in a 10.5 to 1 compression 390 or 429. 

Comment by Russell DeBarros on September 2, 2012 at 8:31pm
So then my question is, "does running the vehicle with lower octane fuel consistently do any damage, or is it just a question of optimal performance? I for one have been running regular unleaded with lead additive and feel that my car is running great especially since I just tuned it up a bit.
Comment by David Murray on September 2, 2012 at 4:01pm

Come to think of it, I put a dose of lead additive in the tank everytime I fill up and the label says that raises the octane a little, so I guess I'm probably at, or around, 100 PON

Comment by Jason Edge on September 2, 2012 at 2:54pm

tagged as octane, octane rating, and fuel rating and set-up URL http://6364cadillac.ning.com/photo/octane for easy reference.


  • Add Photos
  • View All


CLC 2019 Grand National - Louisville, Kentucky, June 11-15, 2019

Started by Jason Edge in General Discussion. Last reply by Jason Edge 4 hours ago. 33 Replies

1963/64 Cadillac Chapter 2019 Grand National Page www.2019GN.6364Cadillac.com…Continue

Tags: National, Grand, CLC, 2019

1963 trunk latch pin

Started by Daniel Grande in 1963/64 Cadillac Specific Discussion 14 hours ago. 0 Replies

I have a coupe deville and my trunk driver side came off looks like the pin came out of the latch I got pin and trunk out but for the love of me cant figure how the pin goes bk in came someone please…Continue

Comfort Control and voltage from the voltage regulator or alternator

Started by Christian Doerk in 1963/64 Cadillac Specific Discussion 20 hours ago. 0 Replies

I probably currently have a similar problem like Sam G in this post:…Continue

Tags: alternator, transducer, regulator, voltage, Control

courtesy light wiring

Started by Andy Kalnins in 1963/64 Cadillac Specific Discussion. Last reply by Mark S Anderson yesterday. 16 Replies

My right rear door courtesy light has two wires- a solid red and a black w/ white stripe. What puzzles me is that both wires have voltage across them when the key is turned to the left or right. To…Continue

Tags: wiring, light, courtesy

Blog Posts

Cadillac Returns to its Roots Under New Leadership

Posted by Jeff Kinzler on May 1, 2019 at 12:30am 3 Comments

Cadillac’s new boss says they should stop trying to build BMWs and go back to building Cadillacs again.

What do you think? 


Radiator And Shrouds

Posted by Dominic Salemi on April 24, 2019 at 3:36pm 1 Comment


Anyone have a decent radiator and shrouds and hardware for a 1964 Cadillac deville. I have an alum. radiator and I'm deciding on to fix it or back to the original one. If I fix it I won't need parts.


64 Recirc/Fresh Air Door Actuator replaced; FROM THE INSIDE.

Posted by Norman Silverman on February 4, 2019 at 11:21pm 8 Comments

I am happy to report that I have successfully replaced the Fresh Air/Recirc door actuator that is located on the blower box-and have done so without having to remove the blower box. I did it by taking out the glove box and attacking it from the back.  It took several days, LOTS of patience and some band-aids, but it is done. THE most difficult part -BY FAR- is to remove and then replace the screw that sits on the actuator arm, connecting it to the fresh…




  • Add Videos
  • View All

© 2019   Created by Jason Edge.   Powered by

Badges  |  Report an Issue  |  Terms of Service