New intakes, I would go with the Clifford dual 2X2 intake with integral water heat. He sells them with Weber 38/38 carbs but he will also sell just the intake and a pair of carb plates. Skip the Weber 38s. Consider a pair of 1974 Ford pinto Holley Weber 5200 carbs. These are small progressive two bbls. They work really well. That, and the intake is already set up for hot water heat.
I run that intake but I run it with a pair of 2300 Holley two bbls on a very modified 261 motor.
New and Used 2x1, really any will work. I prefer Weiand 2x1 intakes because they use a pair of tabs and a cross rod on the intake itself which makes sorting out linkage easier. For single bbl. Stay away from the Rochesters. Too big and troublesome.
Smaller carter carbs would be better, like w-1. But you can also use a couple of adapters and run the pinto carbs which I think is a better choice.
Offy manifolds, another good choice. But buy the intake directly from offy. They have a new owner, young guy, rebuilt all the tooling and equipment, casts and machines everything in the USA. Excellent customer service. Most times you call you get the owner. Anything fro speedway or other places other then direct from offy, offshore stuff made under an old license arrangement. Skip that and get the real thing.
One issue with the offy manifolds (dual and triple), if you want to run hot water to the cast in heat chamber, you have to weld up the sheet metal core plugs that are staked in the bottom of the manifold or else the water will leak.
Now, let’s talk about mouth breathing. The detractors are wrong. Adding a second carb will add power. A little power. Why, because these are little motors and they are really in essence tractor motors. So the improvement is going to be relative. So there is a limit to what kind of additional power you can drag out of them. But here is the thing, the 235 and 261 responds to hot rodding just like any other motor. The problem, if you are thinking you are going to get a lot of power after modifying things, you are going to be disappointed.
On the other hand, if you like to tinker, you will love tinkering with a dual carb set up.
