Transmission for push-button Barracuda

Chrysler introduced the 273 engine in mid-64 production. That 273 motor was specifically designed to fit in the early A- bodies. It's an LA or Light A motor. The LA 318 later replaced the 273, yet maintained the same overall dimensions. A 1971 318 would fit... you would have to perhaps adjust the type of water pump and exhaust manifolds depending on what it came out of.

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318 Poly in an Early A Body?