cambirdracing

iTrader: (4)

I have a 489 in my late wifes 71 Camaro. It has about 10.5:1, Bullet solid roller I/E .686 and 255/266 @ .050. Has Brodix Big Brodie oval ports aluminum heads. We were running 110 octane at 36 degrees timing. I am now going to run premium 93 octane, was just wondering about how much timing I should run. I have it set a 28. This is total locked out. At $8.50 vs. $3.25 a gallon, I'm not in it to go fast any more, I just want to have fun. And win some rounds. This is a bracket car.

Z28 6spd

iTrader: (3)

28 degrees may be a little too conservative. At 10.5 compression, with that cam and aluminum heads, I would think you could safely run 32-34 degrees on 93 octane.

6D9

iTrader: (1)

36-38 no problem on it. Mine and a few buddies with similar combos all on pump 91. Bbc love timing.

v8sten

iTrader: (5)

I agree you should be ok at full timing (36 deg)

cambirdracing

iTrader: (4)

I was reading a CC article after I posted last night. They did a comparison on a 388 SBC, one with iron heads ond one with aluminum heads. They both made the same (within about 10) HP on pump gas with around 36. Guess I need to go ahead and bump it back up to around 34 and see what happens.