Thermoquad carburetor?

Gas can't get from the carburetor to engine oil. The only way that could happen is if the needle and seat wasn't closing and raw fuel was dumping into the intake, then washing down the cylinder walls. The car would be pretty much undrivable under that condition. The better suspect is a dry-rotted diaphragm in the fuel pump. That has gas on one side and oil on the other side.

Be sure to drain the oil to get that gas out. Changing the oil was common practice years ago right after repairing a crank / no-start condition due to a badly flooded engine.

Gas can't leak from the carburetor into engine oil. How much gas is accumulating? Do you just smell it or is the level going up on the dipstick?

First, be sure to get that oil and gas out of there so it doesn't wipe out the bearings. Next, leave the lines connected to the fuel pump if possible, then unbolt the pump and pull it back. I'm bettin' you'll find gas running down the lever. The only other way for that much gas to get in the oil is to have it overflowing the float bowl and running into the intake manifold. If the engine runs okay otherwise, we know that isn't happening. Those engines used to have a common problem with carbon blocking the exhaust passage through the intake and under the carburetor. That made the thermostatic choke remain closed. If the engine did run after it was warmed up, it ran so bad and there was a huge cloud of black smoke from the exhaust. Even that seriously over-fueled mixture wasn't enough for much gas to accumulate in the oil. You got it much worse than that. I can't think of any other way besides the fuel pump to get that much gas in the oil. I'd expect this even more from a recently-replaced pump than one that has been working fine for years.

I have two 1980 Volares. Been running gasohol in them ever since it came out. Even if the diaphragm in your pump was not tolerant of the ethanol, it wouldn't deteriorate that quickly. I suspect there was a simple manufacturing defect in the new pump. That's why they provide warranties.

How does the engine run? If it runs fine with no black exhaust smoke, gas isn't overflowing the float bowl. There can also be drilled passages that get sealed with plugs under the metal base of the carburetor. Those were known for leaking on older GM carburetors in the '70s. The symptom was a very long crank time to refill the float bowl, and the engine was flooded from the gas dripping into the intake when the engine was stopped. The engines still ran fine, and gas filling the engine oil was not part of the symptom list.

The TQ is a pretty good carb overall. The only things I've ever seen that made one leak was a stuck float and one that had a crack in the main body from someone who went gorilla on it. A higher pressure pump could force fuel past the needle so you might want to be sure the pressure is okay. Hope to hear good news.

The crack in the one I saw wasn't easily visible until I put solvent in it and discovered it dripping and found it that way. On that one it was on the inner wall of the float side of the carb. Have seen a few new mechanical pumps that were over achievers with pressure.

Varsol would work, I think at that time I used acetone. The TQ has a unique position in the auto world, it was originally designed by Carter for the racing division of Chrysler, they then took it and tuned it down for the street. Carter also made a few for GM and others.