I have a set of used Weber 40DCOEs with a Datsun Z manifold. I used these carbs years ago, then put the car in storage for a few years. The carbs could use a clean-up but should perform well with little effort.
As you'll see in the photos, 2 of the carbs are type 151 and the other is a type 2. I bought them this way from a previous owner. There are minor differences that I can see (e.g. the aux venturi clips in the type 2 and bolts in in the type 151.) All 3 carbs are jetted identically. Here are the specs:
I do not know the manufacturer of the manifold, but it bolts perfectly to an L28.
The carbs have Grose jets installed ("2 balls to the trick" if you remember the ads from Autoweek). Grose jets, from D & G Valve, replace the stock needle & seat with a really clever 2-ball valve that doesn't degrade the way the rubber ones do. I haven't inspected them, but I bet they're still in great shape.