I use Castrol GTX regular oil and add a bottle of ZDDP for the flat tappet cam. My car will ping on 93 octane . When 94 was available it would stop pinging with the timing backed off a little. I have tried every octane booster out there with NO success. No harm either.
I add 1 gal. of Sunoco 112 to 3 gals of 93 Sunoco ,and the car runs good without pinging.
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