1986 d50 not running right

Ok so I got the d50 about a month ago. It had some small issues when I got it. It only has 51xxx miles on it. The guy who sold it to me bought it to fix it up and the stock carburetor was messing up so he decided it would be a good idea to put a v8 gm carburetor with no choke on it. He also installed a electric fuel pump. The truck will start up but when you start it the rpms rev up to 4500 and I have to constantly pump the petal to keep it running. I checked the fuel filters, they are fine and I took the carburetor completely apart to clean it, the truck still does the same thing. I need some advice on what to do. I'm thinking about just swapping the carb with a Weber 32/36.

I'm going to guess that the jetting is way out

The carb is drowning the engine in fuel. Way too bigger CFM for a 2.0 as well. If you go for a 32/36 make sure it's jetted for the 2.0 and also have a look at the electric fuel pump the PO installed. The Weber relies on fuel flow not pressure to work - about 3.5 psi is optimal. You get the jetting right and tune the ignition to run the 32/36, and it'll pull like a train all day and give you decent fuel economy when you drive it conservatively (if you can stop having fun for 5 minutes...)