If your looking to run a LS7 for racing or older carb based vettes GM now has a intake for that

25534394

LS7 4-Barrel Intake Manifold
GM Racing design for use on LS7 heads
As-cast design requires no porting for maximum performance
Includes mounting bolts and instructions
Uses LS7 carb intake gasket set P/N 19172113
Machined for 4150-style carburetors and has 3/8' NPT vacuum boss
Also available with injector bosses P/N 25534413

Note: LSX Ignition Controller P/N 19171130 is required for carbureted applications