It is indeed a 336, based off the 59 pontiac 389. However if you need a head gasket, the Pontiac 347 or 370 head gasket will match up a little bit better with the bore.
Edit: The 370 has the same bore as the 389. The stroke makes up the difference in displacement.
Last edited by bigbadswingdaddy; 03/19/2011 6:37 AM.
