Club Cobra - Ford 351W dual quad intake manifold etc.

Hey Phil,
I found this information for you. Good Luck.

351W DUAL QUAD INTAKE MANIFOLD
Now for the BIG project, the dual quad setup. As most Ford people are aware, NO ONE makes a dual quad intake manifold to fit the 351W motor. This left me in a dilemma. I could have used a 289/302 dual quad manifold with adapter plates from Price Motorsports in Indiana but that would have raised the air cleaners up so high as to cause hood clearance problems. Thanks to David Shelton (Kountzecobra on Club Cobra) who shared with me the details of how he modified a manifold for his 351C motor I decided to do the same thing. Also, a BIG thanks to Pat at Hercules Machine Shop in Palmyra, NJ where the machine work was peformed.
I began with an Offenhauser 351W 360* single quad intake manifold and had it milled down until the roof of the intake runners were exposed. The rear walls of the #4 and 8 runners were also milled down since the secondary carb base would extend beyond those walls. A new rear wall fabricated of 1/4" aluminum plate was welded in place to allow full access to the runners for the secondary carb. A 1/2" aluminum plate was welded in place to form the new roof on the runners, drilled and tapped to accept a dual quad blower adapter plate. A pair of Holley #8007 390 cfm carbs were then mounted backwards like on an original 427 using an original medium riser dual quad linkage and a pair of Stellings & Hellings air cleaners. I also happened to find a single quad blower plate that had the same bolt pattern as the dual plate. If I ever want to convert back to a single 4 barrel I will be able to do it without removing the intake manifold from the car. Photos of the work in progress are below. The finished manifold is 3 1/2" tall from the end rail to the carb mounting surface which provides adequate hood clearance once the carbs and air cleaners were mounted.

As of February 2004 the machinist who cuts the adapter plate blanks for me is working up a production design to modify the Offenhauser intake manifold so I can offer this product to customers as well. The major difference in the production model is that there will be no bolt-on blower adapter plate. Each production manifold will begin with a top condition used Offenhauser intake manifold to help reduce the cost. The 1/2" thick aluminum roof plate will be opened, drilled and tapped for the carb mounting studs so the carbs will be mounted directly to the plate. This change will lower the tops of the air cleaners an additional 1" over my prototype setup. The only downside is that you will not be able to convert back to a single carb setup merely by swapping adapter plates. Each manifold will be welded while bolted onto a dummy 351W motor and all gasket surfaces trued up to ensure proper gasket seal. Each finished manifold will be inspected and tested for leaks and flaws. No manifold with signs of water jacket erosion will be used as a core.

At the time this Page was published no selling price has been determined. We are still trying to figure labor costs in order to arrive at a fair selling price. When the time arrives I will be happy to discuss even further reduction in cost if the customer supplies his own Offenhauser intake manifold core.