273 4bbl intake manifold question

A bought a 65 Valiant Signet a month or so ago. 273 2bbl and 904 trans. The engine was gone through approx 20000 mi. ago. I want to go with headers, a cam, and 4bbl intake, and carb but am having a very hard time locating an intake manifold. I am hoping to get some suggestions from you guys on the forum. (on the cam, intake,carb, and headers) The car will have an 8 7/5 rear and 4:10 gear. Thanks in advance, Litz