Problems after carb teardown and clean (again)

Sorry I didn't mention. It's stock intake and stock exhaust

I'm beginning to think my problem is a combination of 2 things. 1. The carbs are only bench synced, and 2. Just realized the guts in my right muffler are all rusted and gone. So between the rusty crossover tube (horribly rusted) and the bad mufflers, the back pressure isn't even close to stock.

I think it's time to look at getting a 4 into 1. I always told myself I would eventually get one, but money is tight right now. If anyone knows anyone with a used 4 into 1 exhaust for an 81, let me know!