Is it worth running a 50/50 mix of 110 octane race gas and 93 octane pump gas in a built up 1969 351W? When I got the car it would ping on only 93 during WOT but with this mix, no ping and I can basically put as much timing in it as I want to. I have a stock dizzy but pulled the points and I'm running a Pertonix set up. It also has a holley 750 carb. Is this fuel mixture safe and what is the optimum timing set up initial and total? I can or can not use vac adv., doesn't matter to me since I am not looking for fuel milage, I'm looking for HP.