[PDubs87Z28]

I got a 87 Z28 305 4bbl and everytime i jump on the gas it will make a pinging/crackling sound....i use 93 octane to not have this happen all the time....when i dump lucas "real" octane boost in, it won't make a peep. I was thinking timing but the timing is as close as we can get it to run as good as it is now. the engine has to last until i save up for my 350....so any tips would come in clutch.