Engine numbers

All the info I can find points to the engine being a 318 with that casting number on the block. The model year I.D. and displacement is stamped into the block on the left front verticle face of the block right below the head gasket. If it's a '67 model 318, it should be stamped C 318, if it's a 273, it should say C273. I see a casting 2806130 listed for a 273 but I don't remember ever seeing one. My '64-6 273 engines have 2465330 as a casting number. I have some blocks around your year and when I get a chance, I'll look to see what kind numbers they have. You're correct on the heads. In '67 the 273 and 318 used the same casting....920. The 273 was a solid cam motor and the 318 was hydraulic however. This info is for U.S. built vehicles so if you're working with Aussie parts all bets are off!