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Hey Guys,

I have a new engine for a street car that's sporting 11.25:1 compression. It's a iron headed 440 with stock intake and exhaust manifolds, running a pure stock cheater cam and 800 avs edelbrock carb. Stock reproduction coil and factory dual point converted with pertronix ignition kit. Total timing set at 38.

On initial break-in we mixed 110 octane with 93 so it wouldn't ping. I was wondering if any of you guys have had experience mixing race gas with premium. Someone told me the stock coil doesn't put out enough voltage to properly burn the race gas and I should try and run it on 93 if possible, stating that with alcohol added it is more like 96 octane. I'm not up on that stuff, so not sure what is a old myth or real. I would appreciate any input from guys that have experience mixing this stuff.

I don't mind adding race fuel if needed for it not to ping. I want to understand better how they act when mixed and if the stock coil is a limiting factor.

Thanks !

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Stock coil doesn't have enough voltage to burn race gas Another urban myth The coil(any coil) will produce enough voltage to jump the gap, regardless of pump swill or race gas being in the motor Your pushing the limits on compression with the iron heads and exhaust sytem and total timing What spark plug brand and heat range(part #) are you running? The cheater cam may help a tiny bit as far as the compression but I would be very careful on detonation, if it starts pinging(when it gets hot outside)lift up the throttle and get some better fuel I have treid mixing race gas and pump swill years ago, the race gas is a different specific gravity than the pump swill so they ended up seperating when the car sat overnight, I think Try getting a clear gas jar, as big as possible, and mix the two fuels together % like your going to use, shake them up and let the jar sit for a while, at least two hours or more. If the two fuels seperate in the jar you know it will seperate in the car Let us know if you test it and what it does