This is my 2863263 fan fluid drive unit that was a parts department replacement date coded 7/30/73 ("G30DB") for my '69 Barracuda 340 w factory air. Photos taken before it was rebuilt.
The stud was stuck tight, so I left it as (maybe) the Eaton factory installed it. Note the polychrome green inspection mark at bottom of first photo.
The unit was rebuilt for $300 in 2012 by:
Vincent Catalano
Pampered Corvettes
1396 East Main Rd.
Portsmouth, RI 02871
info@pamperedcorvettes.com
Not sure if he is still in business, but he was quite knowledgeable about Eaton's markings and date coding. He said this exact Eaton unit was also used on Fords.
The fasteners I found on my car:
4 - all thread studs 5/16-24 x 1", same machine screw point each end, phosphated.
4 - hex nuts 5/16-24 x 0.27 thk, 1/2 AF, Gr 5, clear zinc plated
4 - 5/16 conical washers 0.33 ID x 0.62 OD x 0.08 thk, phosphated