I've searched around and it seems no one can answer the question, what is the difference between the 59-61 & 62-66 401 oil pumps? I know there's a difference to the side filter housing 59-60 is different than 61-66. But how does that effect the pump? What are you guys using as a Hi-Volume pump in a 59-60 401?
As per Russell Martin - The Buick Guru @nailheadbuick.com - "The mounting holes are in a different place, the 62 was designed for a center sump pan, different holes in the block. The 59-61 oil pump is the best Buick pump".
The Jalopy Journal
