octane for this combo..
 

455 Buick, 11.5 to 1 compression , Edelbrock alumn. heads. 3450 lbs car, I'm running 36* total timing . I've been using 110 and I'm being told thats too high and maybe slowing car down.. I have guys telling me to run this on 93 pump gas?? What do you guys think?

Re: octane for this combo..
 

I can tell you from experience ( 4400 sets of Eheads ported, built and/or sold,) that you do not want to use 93 octane. Unless somehow you were able to keep the engine at 160 temp or less 100% of the time. If not, 110 isn't going to hurt you. If you want to find out, mix 110 and 93 50/50 and do an A/B test. I bet you won't see any difference. But don't tempt fate with straight 93 unless you can run way cool.

Re: octane for this combo..
 

stay with the 110,,,,,try this empty the tank and try 112 ,,see if the car picks up ,,,if it does then the octane needs to be hirer,,,but dont run the pump gas, detonation can not be heard or felt some times and the damage can done before you know it ,,,,been to the movie and it was a horror story

gmonde

Re: octane for this combo..
 

I am a old school drag racer and would never try putting pump gas in this combo.. I do like the idea of trying higher octanefuel in to see if car picks up.. that is a good safe test...safe is good..

Re: octane for this combo..
 

When changing fuel you need to study the specific gravity of the 2 fuels. It might require a jet change just to get the same flow through your jets. The Air/fuel ratio might change. The specific gravity also is a factor in the lbs per hour of fuel the engine sees. Some fuels require more or less lbs per hour to make HP than others. This makes it important to do a jetting loop and timing loop to evaluate the fuel & octane needs of your engine. In short: just draining your fuel and adding another isn't a good test. You may be leaving power in the can by not evaluating what makes your engine happy with the fuels......
I might add that spark plug location and chamber shape has a large effect on the timing that is required. I'm not up on what changes Edelbrock did on those heads, but the best tueup may have no relation to stock chamber iron heads.

Re: octane for this combo..
 

Understood.. But I have been using Sunoco 110 since I put the V8 in the car. ( always used VP C16 in the Turbo V6) Never had a issue with the way the car ran.. Like a dope I put this "no frills" fuel in the car and had problems. I'm going back to what worked to see if I have a problem or not and then go from there.

Re: octane for this combo..
 

What we found in the 6cly stocker (that would be inline 230) that the more octane the more timing... with 110 sunoco we had to run 40 degrees total I had 50 in it with C12....but it's an 8.8 engine so unleaded sunoco Ultra 94 ran the best. (@ about 34-36 degrees)

Re: octane for this combo..
 

Test

Re: octane for this combo..
 

Call Tony Cowell @ Cowell performance in Weatherford, TX. He has a handle on the 455 combo.