There is a great shop that will split your stock manifold and their work is first class. Contact Mike at Kansas Kustoms (316)663-3256. You can get this done for $185.00 includes return UPS, per his latest ad the 12 Port News.

It's easier to get forgiveness than permission!
1946 1/2-Ton Chevy
1953 Chevy 3/4-ton Factory Stakebed