ndurbin - That will work for inline pumps, but 4020s run a rotary pump that is a little bit of a different animal.
As indicated before a manifold from a 4320 will work (also same as 30 series manifolds too). In past experience, the combine manifolds put the turbo in a different location that what tractors have, so not sure if that will work or not. The thing you have to watch on the early models, which the 65-66 are considered is the location of the valves for the hydraulics, basically are the levers beside the seat or do you reach for them on the dash. If only a single SCV (only 1 lever on dash), the manifold will fit fine, if a dual scv (2 levers on dash) it is gonna be tight, if it will fit at all. M&W manifold is the easiest choice in that case. If levers are beside the seat, then is a cake walk. Last manifod we bought of that type was in the $200 range.
Once you get your manifold ironed out, (espically if you can use a Deere one) you can play with turbos from a 30 series to 50 series tractors, all have the same exhaust housing mounting pattern. Our 67 runs an M&W kit with about 15K hours on it now. Our 69 runs a 4430 manifold and a 4630 turbo. Intake pipe is not hard at all.
I might be able to scratch up and M&W manifold if you have interest.