The pump I pulled off of an all original 60 Bonny 389 was like pump #3. Pump #2 is for a 61-63 Pontiac Tempest 4 cyl. Look at the gap behind the impeller on pump #2. That gap is not on #1 . That is because the impeller for the Tempest 4 cyls is thinner & is set farther into the timing chain/pump housing so it only pumpes coolant to the right side of the housing for the right head. I have seen the style in pic #1 also, It may be for an early (55-58) reverse cooling system???
Keith
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Keith Collier
61-63 Pontiac Tempest
Tech advisor
POCI.org
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