IDK, but an “88 Squarebody” full size Blazer from what I see got 11/city - 16/highway and came with 235/75/15’s. So can 33” tires, 3.73 gears, new plugs, Acdelco plug wires, Accell coil and a K&N oiled air filter gain you 5-7 mpg on a 36 year old truck? Remember, having new clean fuel lines is...