I am thinking about a dual 4 bbl intake manifold with TBI to square bore adapters, and running dual TBI units. 94 Suburban 1/2 2wd. I am replacing the blown 5.7 that came in the truck, with a standard 5.7 TBI for now. I am contemplating rebuilding the stock 5.7 and going to a 383, with performance cam, rebuilt and port the heads, etc. Research says that even a "Turbo City" rebuilt TBI runs 590 CFM compared to 520 CFM in stock configuration. I have not seen a "Vortec" pattern intake manifold in a dual carb configuration. I know "Professional Products" make adapters to allow a standard small block intake to be used on a Vortec application, so I could use an easily found dual quad intake manifold. What obstacles would I encounter trying to make the 2 throttle bodies work together?