[cc69]

What is the highest compresion you can have on pump gas 93 octane, using aluminum heads?

[bullheimer]

FLAT TOPS WITH A 76CC IRON HEAD = 9.2:1 AND I RUN REGULAR CRAPPY GAS. ALUMINUM HEAD=HIGHER COMPRESSION, HIGHER OCTANE=HIGHER COMPRESSION. SO TO ANSWER YOUR QUESTION. I DUNNO! THE BETTER TUNER YOU ARE THE BETTER YOU CAN TWEAK YOUR FUEL/AIR MIXTURE THE HIGHER YOU CAN RUN. PS IF YOU LIVE IN CALIFORNIA YOUR GAS AINT 93, IT AINT 92, IT'S GONE DOWN TO 91!!!

12.8:1 AND HIGHER IF ALCOHOL E-85 FUEL (85%ALKY, 15%GAS- OVER 100 OCTANE) IS USED. GOT CORN SQUEEZINS? (COURSE THIS AINT 93 OCTANE NOW IS IT?)

[Screamin' Eagle]

i was told notto count on 93 gas. Sometimes it might be 93 but the next time it might be darn close to the same as regular.

i was told 9.5 with iron heads so probably a bit more than that.

[78 monte]

At approx 9.5:1 w/ iron heads my motor,as of this year pings like no tomarrow above 3000revs.The gas is getting worse it ain't 93 no more but you pay for it.I've been usin Cam2 w/ 93 in a 25%Cam2/75% 93oct mix(well close to that ratio).The Sunoco 94 is the next best,but still sucks.Or you can retard the timing and have a detonation free Slug.So w/ iron heads I'd say no more than 9-9.2:1