Welcome. Check for air leaks as in crank seals and carb boots, etc. It also sounds like the carbs need to be set up and put in sync. I am not familiar with the cat 440's per say but you need to set the slides and then work from there. I am thinking you have them hanging high in the bore and are trying to compensate with fuel and air screws. Start at stock settings on all screws and work from there. Unfortunately I can't help with specs. Sorry.