Engine Sputters/Hesitates at 2000 RPM

Hey all, so the temperamental Dart decided to act up again. 68 Dart 408, Holley 800cfm dp, Holley blue fuel pump stock tank, large cam, MSD Ready-to-Run distributor. This one has started about a month ago before I got my exhaust done.

At first it was just something that would happen when I would enter on the freeway, while accelerating the engine would "sputter" and hesitate climbing over 2000 rpm, but eventually make it and be fine for the rest of the trip.

Overtime the sputtering on acceleration got better when going on the freeway, but started to occur more so shortly after start up. Basically it would sputter and buck causing the car to rock back and forth and eventually shut off. If I restarted it and let it warm up again, it would eventually cooperate and drive normally. This occurred the morning of Spring Fling (60'sF) and after one restart, it made its way 60 miles to the show. On the way back it was much warmer (high 80'sF) and didn't have any problems.

I started the car two weeks ago and now the problem has escalated severely. Now the car will not drive above 2000 RPM and will not drive up a hill. It's idling a little higher now (1000-1100 rpm), where it used to be at 800-900 rpm before. If I rev it in Neutral, it will go to 3500 before sputtering a little but will still climb higher.

Any ideas on how to remedy this or where to start checking? I thought it may be a fuel issue, maybe a fuel filter is clogged? Carb needs cleaning or is clogged? Maybe spark plugs need to be replaced? Hopefully it's an easy fix as I don't really want to spend money on this. It kind of sucks this happened as I have no time for the next 5 weeks due to me finishing my master's and at the end of June or early July, I was going to change the entire fuel system for efi (Holley Sniper/Fitech, new lines, Tanks Inc EFI tank, and Stealth Aeromotive pump).

Anyways, let me know your thoughts. Hopefully I can spend an hour here or there to try to remedy it.