A couple of things.

What you are describing is typical of a low comp engine with a larger cam and not enough intiial timing. You can jet it all day, if you like. But it won't run any better till the timing is sorted out.

.050 off the heads of a motor with the pistons .170 in the hole, doesn't do much. It'll be 8:1 on a good day.

Ideally, I think you want to advance that cam 4 degree's or so to make it better down low..

The rock stock converter isn't doing you any favors. The misconception is that you can't drive a converter with more stall on the street.
A well built performance converter will drive like a stocker under light throttle, and flash to a higher rpm on hard launch. A 3K converter would be a nice match for that.

If I was curving a distributor for you, I'd recommend 18 intial, and 35 total all in by 2800.

The 3.55's are fine. I run way more cam with 3.73's, and didn't lose any ET when I switched from the 4.10's I had before the 3.73's.