ā€˜66 Barracuda

My ā€˜66 Barracuda.. it has the 273 2bbl. It starts and runs ok. It looks to have the original engine and trans but being new to the Mopar world, Iā€™m debating on whether I should keep it all original & just rebuild what I have or is it time to swap out the engine for a 318, 340 or 360... I appreciate any suggestion from my Mopar friends.

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