Here is kind of interesting observation. That chrome air cleaner tin is what you usually see with a 4bbl carb.
Then the fact the gas line is running on the side of the carb, instead of coming in the front like the stock 2 bbls had. Leads to something more like a Holley 4 bbl. ???
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2bbl carb, gas line comes in front. It would be in the center of the manifold not the side.
A picture of the carb with the air cleaner off would tell us for sure.
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Then there is the question which front crankshaft vibration dampener does it have?
318 dampener:
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340 External Balance Dampener
with offset weight:
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360 external balance dampener, with large offset weight:
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Can look and see with a flashlight which one it has.
Bottom front of the engine, just behind the belt drive pulley.