I used to run a 302 GMC with three Weber 32/36 carbs in my 40 Chevy coupe. The manifold was home made. I still have it as wall art in my garage. I tried to make it look like the classic Harper manifold. The three intakes were made from 90 degree mandrel bends. The bends tapered the flow down from the Weber 2 barrels into the single round GMC intake ports. My first design use 1/2 inch I.D. rubber hose between the the three tapered intakes . It ran quite well. I could really feel the car pickup when the larger barrels kicked in. But I could not leave the design lone. I decided to replace the rubber hose balance pipes with 1 inch steel tubing. I lost the acceleration kick when the Weber's larger barrels kicked in. I would go back to the smaller rubber hose balance tubes if switched back to the three Weber manifold. The big drawback to this design is the complexity. The number of pieces is roughly 3X what a single 4 barrel manifold would need.
I am now in the process of making my old Chevy easier to drive. I am trying use a 200R4 with overdrive and a Holley 395 cfm 4 barrel. The small Holley works well. I have not had much luck with the the 200R4. If anyone is thinking of a similar modification think about have a professional do the installation.
