[Hank70SS]

I can't accurately measure my fan, 772, or shroud, stock 70 big block, with everything installed. I can tell you my shroud is roughly 1.5" larger diameter than the fan, 3/4" from fan blade to shroud times 2.

I can also tell you the stock 772 fan, stock matching shroud, Hayden 2747 HD clutch and a good 3 or 4 core rad, depending on engine, is about as good as you can get. Heard so many guys chasing an overheat problem, electric fans, aluminum rad and still running hot. Timing, not enough advance will cause the engine to run hot. Also a lean idle mixture will cause it to run hotter at idle. The original stock setup worked good but everything has to be in good condition, radiator and fan clutch. No different than any other system, if one part is not up to the task the whole system fails.