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#11
02-05-2018, 07:23 AM
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My 12:1 428 did the same thing on lower octane gas. Did not diesel with good gas.
My current 455 will do the same thing. It is 11 to 1 compression and 236/245/112 HR cam. It is tuned to the brink of extinction, timing an fuel curves are spot on, and I race the car in addition to street driving it. The engine idles fine at 700rpm's in and out of gear, so idling too fast is not the issue. I run it on a pretty steady diet of 87 octane and it does NOT even think about pinging under any conditions. Race days only I'll mix in half a tank of 92-93 octane on the way to the track just to give me a "warm and fuzzy". What I do see in the hottest summer months when it's fully heat soaked is that it will run on once in a while when shut-down. If I use 89-93 octane it doesn't do this. If it's in the cooler time of the year of Winter it doesn't do it either. It also "bucks" the starter ever so slightly when it's hot enough outside and engine hot enough to "run-on" after shut down. The easy cure is to run 89 or higher octane in in July and August and it never has an issue........Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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