From what I read when I did my conversion was 87 up tanks are physically the same on the outside as my 78 but have baffles while carb fuel tanks don't.
I have done the same, 87 fuel sending unit with 255 walbro. I used a corvette fuel filter/regulator combo as well.
As for fuel starving, I don't let the tank get low at all because I was worried about starvation.