[kdeman1@yahoo.com]

Did they make 2 different height water pumps back in the day…? I’m driving my self crazy, particularly for a 77 400.

The fan doesn’t seem to sit in the right spot…

['ol Pinion head]

All production '69 Pontiac V8's used the 4.0" hub height 11 bolt water pump. Ames, Butler, & a few other new parts sellers still like to throw out the tired "69 1/2 waterpump" line of BS. The facts are Pontiac used the short 11 bolt pump until the '70 model v8's came out in Late August of '69. At that time, the '69 v8 Firebirds continued to be assembled up into Nov of '69 with engines with the short 11 bolt water pump, the rest, A, B, & GPs received the tall 11 bolt wp & corresponding '70 water pump pulley. When '70 Firebirds were released in late Jan of '70, they had their own design of alt/PS brackets & pulleys.

all '70-81 Pontiacs used the tall 4.5" hub height 11 bolt water pump. Pontiac went to a different bearing insert in mid '72 water pump production, as a result the first "296" casting water pumps were produced, these continued through '81 V8 production & for service parts. Most of the last factory installed "296" casting pumps had a small low drag impeller. That pump was used on 301's & '80-81 265's. Have offered rebuilds for many years, & with the latter "296" casting pumps have even built a few 400-455 builds where hard block to the bottom of the freezer plugs was used in performance builds.

[kdeman1@yahoo.com]

Great info, thank you I’ll measure 👍