Ya. That makes sense. Thanks. Even if I could gain 1/4” or so, I’m not sure it would fit past the nub on end of water pump shaft. If it did, my blades would literally by 1/4” to 3/8” from the rad fins. I’m wondering at this point if I should just try to find a fixed 18” fan and use a spacer to get it half in and half out of the shroud