Originally Posted by 69LT1Bird

Yep, your tuner told me that one. I run 29* right now but I have ran as high as 31* at the drag strip with no spark knock. In fact the 11.67 pass in my sig was on 31*. I only have 10.8:1 CR.

Originally Posted by WKMCD

One BIG thing we learned along the way was not to trade CR for spark lead. These heads love to run 28-29 degrees of advance. In one phase we lowered compression from 12:1 to 11.3:1 and gained HP/T by running 4 degrees more timing.

Just my $.02