[77 TRASHCAN]

I had a GMB on my car, bearing pooped after 2000 miles, not something I'll use again.

[78 WS6]

Originally Posted by 77 TRASHCAN

I had a GMB on my car, bearing pooped after 2000 miles, not something I'll use again.

I see where GMB has multiple pumps available, which one did you try?

[77 TRASHCAN]

Originally Posted by 78 WS6

I see where GMB has multiple pumps available, which one did you try?

Not sure. There was likely just one available for my 77 T/A (11 bolt, original) when I purchased it.

I worked at an auto parts store from 1985-1998. Somewhere in that time we had a line of strictly "new" import water pumps. I ordered a Pontiac, was surprised it was aluminum. Thinking I'd found an affordable aluminum water pump. So much for a bargain...
The life span on Mine went for several years, because, I seldom drove the car, as you intrend to with yours...
I sold another one of those exact pumps to a friend with a 70 GTO. His car saw more driving time. Seemed like about a years time on his before it crapped out.

I was in a hurry when the aluminum pump gave out.
I bought a "New" AC Delco pump. It was an iron pump with the stamped impeller. I adjusted the seperater plate for absolute minimum clearance. This pump was the 4th one I had installed. TIt was the 4th because, when I performed other engine repairs/modifications in that area, I replaced the pump, preventatively.
The iron pump with the modified plate cooled the engine exactly as cool as the O.E. pump. Man, wish I'd kept the O. E. pump. The other pumps had no cooling issues, just ran slightly warmer...

['ol Pinion head]

One thing learned many years ago is many of the '77-81 Pontiac v8 water pumps originally used a "296" pump with a cast impeller with abbreviated fins. The slightly shorter fins worked fine in even in my modded Turbo 301, this design impeller also has slightly less drag. That particular style impeller also works well in a street/strip type engine that the block has had its coolant capacity reduced by a short fill of hard block.

On a normal 400-455 11bolt pump cooling deal, like a W72 400, am not rebuilding with that impeller, but using the correct full length cast impeller. Pontiac used at least 5 different cast impellers in original V8 waterpumps from '63-81. they designed the original pumps to match cooling system's needs, and as time progressed, introduced cooling system refinements. As Tom V likes to note "Engineers do things for a reason"! For many cooling applucations, its very hard to beat a correct design cast impeller waterpump. The majority of original Pontiac cores I have are '64-73 range, some of the early casting numbers are getting very very hard to come up with. With the interest in '77-79 400 models, have dug out more of that date range pump cores & am rebuilding upon need.