[Robert Williams]

Are you going to make your own intake manifold or use the aluminum intake that is available now? The aluminum manifold that is available now will flow approximately 260 cfm, a little bit more than a stock 66 cast iron Tri-Power intake will flow. If your going to make your own manifold then how about one that will flow 300 plus cfm for the big engines. The venturi sizes on the original 66 Tri-Power Rochester carbs are 1-3/8" for the front and rear, the center carb on the 66 had a 1-3/16" venturi, all 3 had 1-11/16" throttle bores. I have had very good luck using the 68-69 400" 2-bbl Rochester for the center carb on the big engines because this 68-69 400" carb has a 1-1/4" venturi 1/16" larger than the original center venturi and works very well, 1-3/8" venturi would be better yet. The 68-69 350" Rochester 2-bbl carbs have the same size venturi as the original 66 center at 1-3/16". Good luck with this project, i can't wait to see one but make it to flow some big air for the big engines.