[sean70ss]

Spark plugs are only good for about 3 dyno pulls and that is it. And dynos are way differant form real world driving. Theyu are ok for a basline but with the ever changing air it makes them hard to be reliable especially street driven cars. 14-16 degrees is good for intial timing anything over 500 inches should really be below 36 degrees timing smaller motor likes more timing. I have run 427's with 42 degrees with no problems with a mix of gas and race gas. aviation fuel was desgined to be run at extremely high altitudes it is a dry fuel not made for street or racing engines the price is attractive though but hard on motors you take a chance on burning things up espcially with nos. my LS6 car I mix the fuel 12 gallon of 93 and the rest 116 vp fuel with 36 degrees timing actually runs 10 degrees cooler and runs hard as heck. They key is no detonation if your doing a factory rebuild to the stock specs runa little race gas and have fun or you can chage the cam to bleed off some cylinder pressure etc there are so many differant ways to accomplish this. Sean