Put in a bunch of filters over at
Summit
if its a Vortec 7.4 its a mark VI, the filters i have are for carburated dual plane intakes. You didn't list your cyl head port configuration, so you can narrow it down some more. (or less by deselecting things). I'm sure others will chime in, but it'd be easier to advise if we knew your goals (racing, towing, 4x4 etc.)