Quote:
Originally Posted by Mr. Chevy
Has anyone had any luck with an octane booster? I don't want to throw away money on crap that does does not work. This is in lieu of actually running 110 race fuel which I know will cure the pinging issue in the motor.
I'm having issues with running Sunoco or Marathon 93 pump gas in my 67 Impala 327 motor. The motor is a bone stock 275 horse. The compression is 10:01. I have done everything I could to get it to stop pinging with running pump gas: retarded timing back, carbon cleaning, new ignition parts and the exhaust is flowing good motor is breathing.
Any help would be appreciated....
Thanks...
Rich
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Unless the decks have been cut, etc. a factory 275 hp 327 actually calculates to something less than the advertised 10:1. Probably more like 9.2:1 to 9.6:1
You say you've tried retarded timing - are you talking initial, or have you actually considered the whole curve? A vacuum advance with no limiter will pull in a LOT of timing. Same goes for centrifugal. It would also be a good idea to check out a/f ratio with a wideband sensor. It's pretty easy to make a Q-jet deliver the required mixture, if you know where you need to go with it.
My opinion (based on experience with 9.3:1-9.8:1 CR 327 & 350ci Chevy engines with mild cam timing) is that a well tuned 275 hp 327 should run OK on 93 octane if everything else is "right".