About this fan... This NOS fan shows a 79' number in the fan casting https://pbase.com/9146gt/image/154905423 indicating it is for a later 911 SC. The O.D. size remains the same as a 906/RSR at 225mm, but it is not correct for either a 906 or 911 RSR. Having said all of that, essentially all the smaller 225mm Magnesium Cooling Fans are nearly identical https://pbase.com/9146gt/image/155011188, virtually the same part with one exception being the metal center hub. The metal hub on both the 906 and the 911 RSR only have 8 holes drilled in the metal hub https://pbase.com/9146gt/image/155011197 while the later 911 SC obviously has twice as many with 16 https://pbase.com/9146gt/image/155011174.

Here is a side-by-side comparison photo, the SC next to the 906/RSR fan https://pbase.com/9146gt/image/155011195

Two additional reference photos, a 225mm Mag Fan and 226mm Housing installed in a 906 https://pbase.com/9146gt/image/31433122, and this other in a 911 RSR https://pbase.com/slidevalve911rsr/image/54217411

Mark Motts, 911 Fan and Housing Restoration Thread http://www.early911sregistry.org/forums/showthread.php?78787-You-Got-The-Motts&highlight=mark+motshagen

Best way to contact Mark is by phone: (949) 463-2892, or email: mots356@yahoo.com (that man can weld magnesium like no one else).