The lower octane rated fuel will burn faster and should be easier to start the eng on. I know in the colder weather in the winter my buddies 68 Cuda thats an 11.5 Indy headed 440 will start easier on the pump then it does on race fuel since the race fuel is slower burning. Course my 63 always starts easy on the 92 pump I run. Ron
It's not just the octane- fuel purchased from a pump in the colder months in northern climates has better cold start characteristics than summer blend fuel. It's more volatile, even for the same octane rating.
Ron