Here is where a lot of folks get tired of chasing the odd-ball parts. If the engine is a 315 then 4-bbl intakes do show up on occasion. Yes, the 315 Hemi intake bolts onto the 315 Poly engine. If the engine is a 270 then finding an oem 4-bbl is problematic...however...Offy make a 1x4 and a 2x2 intake (Exeter Auto Parts).
NO, due to a change in deck height, 270 manifolds do not interchange on a 315, vice-versa.
Now, as far as actual performance goes, if you have a 2-bbl intake you might consider adapting a 70's vintage Holley 2-bbl from a 360/400. They move plenty of air for a 315. No, they are not as sexy as a 4-bbl....