[Formulajones]

Tri-5 Chevys never had shrouds.

Daily drove the 56 Nomad for years with a warmed over 327 in it and never found a need to worry about a shroud on it. It never runs over 180.

The aftermarket does make a very shallow plastic shroud that could be added if one wanted to, but I haven't seen a need for it.

[tjs72lemans]

I agree on that. My 55 Chevy runs cool with no shroud cooling a 327.

[Formulabruce]

Originally Posted by promptcritical

Did the factory pound down the divider plate? That seems to be something that comes up a lot.

The factory did not mess with divider plates. In Class it was discussed breifly with reference to corrosion only. Only saw a couple warrantied.
That said; when I got into the picture in the 70's it was well after the CR had been dropped on new cars. The manufacturers "wanted" more heat to help with emissions.. All the water pumps I saw had cast impellers, new and on cars.
There was no MTBE, and No alcohol .

[Formulabruce]

Originally Posted by padgett

a) fan should be 2/3 of the way into the shroud.
b) have never had a GM car that did not have a shroud. Longest was on a 70 Grand Prix.

The peak edge of the blade should be closest to the inner edge of the shroud.
Thats from GM. Could it end up 2/3? possibly..
The GP didnt have a fan shroud, they have a WIND TUNNEL!