That's the same water pump I have. The 392 has identical external dimensions of a 345. Both of which are slightly taller and wider than a 304, but no longer from front to back. Here are the attributes of the two Hayden clutches as previously discussed: p/n 2705 "Standard Duty" - Overall length is 3.11 inches. Fan mount height is 1.53 inches p/n 2747 "Heavy Duty" - Overall length is 3.34 inches. Fan mount height is 1.62 inches. According to those specs straight from the Hayden catalog, the difference in overall length between the two is just a fuzz under 1/4th of an inch, and roughly 1/8th of an inch less than what I mentioned to you previously. Based on that, I'm estimating that I have approximately 3.9 inches of clearance between my WP and the Champion radiator in the standard mounting configuration. Why you would have any less than that same figure beats the living hell out of me.