best tire size for my truck
 

hey guys i have my 85 gmc sierra im working on and im trying to find the best tire size for the truck. i have a set of boss 338's 18x8 with a 4.5" backspacing and a set of 20x10 with a 6.5" backspacing for the rear. i have a 2.5" spindle drop up front and a 4" drop in the rear. any reccomendations? im not looking for a very soft tire just street use mainly.:fry: