The Flex-a-lite fan spacer kit is best when used with Flex-a-lite belt fan. Belt driven fans perform best when they are 3/4" to 1" from the radiator's surface. Whenever original equipment fan clutch is removed from the engine, a spacer needs to be added to bring the new fan back into the "sweet spot" in the fan shroud opening. Multiple spacers may be used, up to a maximum of 3 inches.