6lb pump blowing out carb?

The pump fuel formulation will not all evaporate until it hits close to 400 degrees F.
That's one reason it burns poorly if there's not enough heat in the cylinder and the initial burn.
Not including the Eth mostly changes the light end, but doesn't change the rest of the formulation. :(

E0 may slightly lower the vapor pressure and improve the flame development after ignition. But winter fuel in most parts of the country is going to have high RVP regardless. E0 should keep a little better as well, etc etc.
All this to say I don't see this will get your car down to the garage focusing too much on the fuel.

Check the sock filter first. Change the line if you want. Change the hoses. Put a couple filters on. One in line with low micron (like paper) and the sintered metal ones in the feeds with springs.