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I know this is going to sound stupid but aside from the intake, carb, and HP exhaust manifolds, is there any other way to distinguish a 318 from a 340? Just trying to learn for when I judge at shows to see if someone is making something look like it is not. I know the blocks were basically the same. Is the heads a different look all together as well? I also know the 340 was orange paint vs. the blue or turquoise color that the 318 and 360s were.



The engine info is stamped in the block below the driver side cylinder head. Should read something like "IM340XXXXXXXX" The remaining digits distinguishes the year, serial, etc.

Sometimes you can see it clearly, other times there is either so much paint on the block, or the stampings are very light. Aside from this, the only other way that I can think of is the block casting number which will have "340" in the number (pretty tough to see unless you crawl under the car and hopefully the exhaust/headers aren't in the way), or possibly the cylinder heads will have an "X" or "J" stamped on it, but anybody can swap cylinder head around from one engine to this next, so that's not so sure fire.