318 f.a.s.t class , oem stock appearing

I guess you need to clarify one thing: When you say "appear stock" 2bbl, I'm assuming you are going to run the factory 318 2bbl. If so, man, that thing is a choker. They are under 300 cfm's. Anyways, I don't know if you could massage it to flow even 375 cfm's..... You have a tall task getting 400 hp if you want to use the factory 318 2bbl and factory 2bbl intake...
Now if you just want to say you have a 2bbl, put 3 of them on there.... yeah, a six pack, that will help ya get up there in horsepower