I’m seeing a lot of comments while they are correct, they are not getting to the base of your problem.
First off, figure out your compression ratio. Remove the head on #1 cylinder and find top dead center with a piston stop. Plenty of videos on YouTube showing how to do this. At this time install a degreeing wheel on the cam snout so you can check cam installation. Set a pointer to zero. Then cc the piston to the top of the block with a graduated cylinder and then cc the combustion chamber of of the #1cylinder. Add these two together and figure out your compression ratio. This is the ONLY way to get an accurate CR figure. You cannot just look at piston and head spec sheets. Now turn the crank to 106 ATDC. Your cam should be at its highest lift, on top of the lobe nose on the intake lobe. This is the ICL. There are plenty of YouTube vids showing how to do all this. I have not gone into all the detail how to do this correctly.
A few words on cam selection, engine building and dyno testing.
If you built this engine yourself, you need to find an experienced mopar engine builder cause you didn’t get it right, no offense meant, but I didn’t get it right my first engine either. I now have an experienced engine builder that has built thousands of engines and has experience that I will never have. Reading tech and taking others advice ends up with mis matched parts and trial and error which is right where you are now. My builder has a dyno and knows how to use it. A dyno is used to tune and dial in an engine. If you are just paying for a few pulls and a dyno spec sheet you are not just getting ripped off, but not using the dyno as the tool it was meant to be.
As for the cam, with my limited knowledge and experience, that cam is not opening the intake valve soon enough. It needs to open the valve 20-30 degrees BTDC for a high performance engine. You need to talk to a cam grinder with your engine builder as well, not a salesman from a cam manufacturer. Oregon cam grinders is a good one recommended on fabo and is reasonably priced. Mike Jones is good as well but expensive.
If you want to learn more about about what you and I don’t know about engine and horsepower fundamentals, watch David Vizard on YouTube and buy his books. I do and did. There was so much I didn’t have a clue about and still don’t. David has done thousands and thousands of dyno pull testing for not only for himself and his race cars, but for car manufacturers, and speed part manufacturers. KN, comp cams, Ford and the list goes on forever. Automotive journalist, aerospace engineer, university lecturer, engine builder and race car driver. The guy is accredited.
As for your carb, it is not too big for your engine, it’s not tuned right for your cam and the rest of your combination and that’s your dyno guys job. But I believe the biggest part of your problem is your cam. You have to get your combination right before you tune any carb or you will continue to be disappointed.
