a stock 273 4bbl intake is pretty decent for a stockish 273 and the 500 eddy is probably going to work the best for a stockish 273.

Just an FYI the holley 2bbl will fit on a 360 2bbl manifold and the manifold can fit the 273 heads with a little grindinng of the bolt holes and port mis match is not too bad as the 2bbl manifolds have slightly smaller ports than a 4bbl manifold, but if it was me I would find a factory 273 4bbl manifold and run a small 4bbl.