Information on the 273
With the factory stock 273 cylinder heads (1965) I would find some traces of coolant under the hood once in awhile at the drag strip (Fremont Raceway circa 1973-1976). I later found (when refreshing the motor) a hairline crack in one of the cylinder heads. Not sure if that was a common problem back then. Converted to 340 cylinder heads but ran slower in the quarter mile than when had been using the factory 273 heads (I guess the open chamber 340 heads resulted in a massive loss of compression, even with the 273 domed four-barrel pistons).
With the factory stock 273 cylinder heads (1965) I would find some traces of coolant under the hood once in awhile at the drag strip (Fremont Raceway circa 1973-1976). I later found (when refreshing the motor) a hairline crack in one of the cylinder heads. Not sure if that was a common problem back then. Converted to 340 cylinder heads but ran slower in the quarter mile than when had been using the factory 273 heads (I guess the open chamber 340 heads resulted in a massive loss of compression, even with the 273 domed four-barrel pistons).