1968 Corvette 327-350hp and 1968 Z-28 Camaro 302- 290hp engines also used this block.
HN suffix on the front stamping indicates ours is originally out of a 327-250 hp 4bbl Impala with a Powerglide. It's not likely the engine was highly stressed or abused.
1969 and later blocks have more material in the webs and 4 bolt mains became an option.
I would have preferred using a later 4 bolt block, but Gerie wanted to keep the engine legal. This block is "arguably" within the period as a plausible replacement. The strength should be sufficient since we plan to keep it under 400 hp and 6,000 rpm..
Next stop: Kinetics Racing Engines in Westland, Michigan.