302 heads and cracking

Thanks, forgot about 646. I’ll have to post some pics of the 308 heads I got to cc. We checked multiple chambers with the burette and plexiglass plate and we got 58 cc’s repeatedly. As far as we know of the history of the vehicle they are stock uncut 1991 heads. If a person had some of these there would be a 2 cc chamber reduction of chamber volume vs. the typically 60 cc fast burn head at 60 cc’s. Anyone else ever run into any 308 with such a small chamber volume? The donor was a 1991 W-250 with 360 hydraulic roller engine.