Reply to "PROBE, SENSOR? ANTI-POLLUTION engine 351C 1 ???"

The Holley 4165 650CFM should be fine, but will also have the same problems with the intake manifold. Your intake manifold should look just like one in the picture below if it is the original one. It has an aluminium thing on top for the EGR valve, which you wont need if you get rid of all the polution gear. But you can clearly see the shape and size of the ports, which are the same in the manifold itself. This is what is called a spread bore manifold for a spread bore carburetor. If you compare with how a Holley carb looks from the bottom, you see the problem immediately, it is a so-called square bore carb. The Holley carb wont be able to open as the throttle plates and the holes in your manifold don't line up. A cheaper solution than new intake manifold etc, is a quite thick aluminium spacer which is totally open, or has  ovalised holes to allow the throttle plates to open. I have seen one of these ovalised adapters on a Longchamp, not sure if that is how De Tomaso did it at the factory.