Hello,
I have been using Exxon/Mobil Synergy Supreme premium gasoline mixed with about 5 gallons of Sunoco 260 (100 octane).
https://www.exxon.com/en/synergy-supreme-plushttps://www.sunocoracefuels.com/fuel/260-gtAdding the 260 really helps with fuel boil.
About the car, '68 Barracuda FB Formula S, 3.91's, 5 speed manual, DLI ported X heads, M1 intake, holley carb, mech roller cam (about 248@50), about 9.7:1 compression ratio, bored and stroked to about 386ci. Timing is 22 degrees initial, 37 total all in at 2500. Vacuum advance adds about 8 degrees of advance. This engine likes a lot of advance, meaning I could probably go with a little more initial and total (2-3 degrees). Maybe it wants more timing to burn off some of the deposits?
Cab's suggestion of a hotter plug is interesting; I could give it a try and listen carefully for ping/rattle.
If you need any additional info, please ask.
What pump gas are you guys running in your cruisers with carbs?
