35s with 20s
 

this is prob a dumb question but could 35 tires with 20s fit under a 4 in lift?

There should be no problem what so ever. The diameter of the tire is the only thing you have to worry about, not the rim.

if you are referring to the rancho 4" lift it yeilds 5.5 inches of lift in the front, so you can fit 35's fine.

Big 50 is right. You can fit a 35x12.50 using 17, 18, 20, 22 or 24 inch wheels. I'd suggest a 20x9 inch wheel with 5 to 6 inches of backspacing.