What is the maximum timing I could be running on a 312 with Isky E4 cam? I have initial at 12* + 26* centrifugal for a total of 38* with about 15" vacuum at idle. I can get up to 18" vacuum at idle if I advance the timing to about 18-20*  and seems to run better but that bothers me running it that far advanced. It also has an adjustable vacuum canister that could be dialed in for maximum fuel economy. Where is a safe limit?   Dave

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