56 Pontiac info needed

A good friend has recently purchased a 56 Pontiac and the engine is pretty tired. He wants to get it rebuilt but needs to know what size the engine is. Is there a way to determine the engine size without tearing it down? The books we have llist a 287 and a 317 cubic inch for 1956.

thanks

 

my book only shows the 317 available that year.

 

Yep. 317.

 

Thanks.