IMO, you're going to be down on HP if you use anything other than the spyder type intake (vic jr/supervictor intake with injector bosses). the Victor5.8 intake is well suited for mild
351w's but when you're talking almost 400ci it is going to be a considerable restriction - even with a mild setup. You may spend a bit more for the spyder intake, but it would be well worth it. Gary Rohe / Tony Bischoff call fuel injection "fuel infection" on large CI SBFs. Unless its done right, you're wasting money and HP.
I know on my 408w, even the plenum of the victor jr carb intake is too small. I picked up 22hp just by adding a 3" spacer (to increase plenum size). 22hp... it sounds impossible for a carb spacer to be worth that much HP, but obviously the plenum size is wayyyy to small for that much ci.
my street driven/pump gas 10.5:1 408w with: box stock vic jr heads (absolutely NO port work) vic jr intake (and 3" spacer) port matched to the heads
950cfm carb (Size recommended by Barry Grant) mild street grind solid roller cam (0.601 i/e is mild with that much CI - has plenty of vacuum at idle)
Made 608hp@6000rpm and 580ft/lb@4800rpm. From
3000rpm where we started the dyno pull through
6700rpm the motor put down over 500ft/lb. Whats wrong with a carb? ;-)