[Mr70]

I think those 1974 245Hp 350 Z/28's woulda used the #3995647AP.

An interesting side note to this is that Joe P. is still the original owner of a 1970 L-78 Chevelle today.While breaking it gently down to do a complete resto on it,he found it was assembled with a deepgroove #3947824BV fan pulley,yet the parts books AND his buildsheet state it should have a deepgroove 060AP pulley.
His is an early build of August 1969.
While being judged DIAMOND at the NCOA 16 years ago,the judges gigged him for the pulley,as he left the original BV on it.
He said he didn't like the judges decision,but understood it as they were going by the books,and he by what his car was actually holding.