I put my LQ4 vortec into my FJ75 cruiser using the stock 70 series radiator, cant remember the dimensions off the top of my head but its only slightly bigger surface area than the radiator in my 40 series (both are 4 core copper). I was a bit worried that it wouldn't cool the engine properly but with the stock (new) clutch fan and a nice tight shroud the engine runs between 180-195F, I've been using it as a tow truck to tow my FJ40 and even on the long steep drag towing up over the ranges with my 40 on the back I never quite reached 200F it got close but didn't quite get there
