Small Block Mopar Engine Date Code 3-4-66
If its got a performer on it , it aint a poly. 273 has 3 wide spaced core plugs (very front middle and far back), with NO displacement in driver side casting number (318,340 and 360 do, and have closer spaced core plugs, like all in the middle) Itll also have a number stamped in front under the driver head seam, itll be under 1-2 coats of paint and grime. The passenger side should have a casting date and a D N stamp for shift. 273 until the last year all had "light duty" forged cranks but are still stout cranks that can make up a fast revving 273-340 short block. Rods are also light weight. 273's seem to be priced higher than 318's just because they are more "original" in pre 68 Barracudas and its fun to say you got a 273 instead of a "teen". Add pop up factory pistons and hotter cam and you got yourself the "Commando" 4bbl version. Most were solid cammed, but can be made hydro with later lifters and pushrods. Poly 318 is very wide and the valve covers look like about 3 teeth per foot saw blades. Has a weird looking intake too. Nice motors in their own with some interesting power potential.
If its got a performer on it , it aint a poly. 273 has 3 wide spaced core plugs (very front middle and far back), with NO displacement in driver side casting number (318,340 and 360 do, and have closer spaced core plugs, like all in the middle) Itll also have a number stamped in front under the driver head seam, itll be under 1-2 coats of paint and grime. The passenger side should have a casting date and a D N stamp for shift. 273 until the last year all had "light duty" forged cranks but are still stout cranks that can make up a fast revving 273-340 short block. Rods are also light weight. 273's seem to be priced higher than 318's just because they are more "original" in pre 68 Barracudas and its fun to say you got a 273 instead of a "teen". Add pop up factory pistons and hotter cam and you got yourself the "Commando" 4bbl version. Most were solid cammed, but can be made hydro with later lifters and pushrods. Poly 318 is very wide and the valve covers look like about 3 teeth per foot saw blades. Has a weird looking intake too. Nice motors in their own with some interesting power potential.