Don, i have installed a couple of these both with the stock single4 intake. I had to grind both to get them to work. the heat exchanger area is the part that hits when you set the intake on the engine. this is well up under the manifold and cannot be seen when it is finished. If memory serves, I had to take about 1/8 in. off to get it to clear. You need a little more than the actual clearance to allow for the ''crush'' of the intake gasket when the intake bolts are tightened and also the heat expansion of the manifold.
Why the heck are the fins cast/made so high on these various covers? If the 2x4 is popular and is the 'worst case'-then that should be what they're made for and then will fit everything else. The idea of having to do 'blind' grinding on 'eye candy' stuff sounds nuts to me-
That 1/4" clearance can be made up on the stock 1x4 manifold by not using a gasket under the valley cover & just use silicone. That's what I did on my '64 & didn't have to grind or cut any fins. The heat chambers on different manifolds are in different places, hence one fit does not cure all interference problems.
i think that Tom is right about this. The gasket is what causes the problem. My gasket in this kit was thicker than I am used to seeing so I had to grind the fins. Seems that I remember the gm gaskets being thinner by quite a bit but you cant get them any more. Then too some of the finned covers have a lip cast into them and some dont. [ I think] I too wondered why the fins wer not reduced in height in the middle of the cover. That would solve the problem and the intake already covers the area.
