Water pump manifold found

[Vaaraz]

Hello everyone,

I remember the advice I read here about increasing the size of the return hole in the water pump housing.
If I recall correctly that hole in the housing where the lower radiator hose connects is about 5/8 inch. I've heard that Jon Myer encourages that it should be drilled to 3/4 inch to allow more water flow.

A few days ago, by putting my old spare parts in order, I found an original water pump manifold of the car.

I guess it was a spare one I had from the former owner.

Of course, the first point I checked was the diameter of the "return hole" in the lower housing... and...
I was surprised to notice there is NO hole at all... the water passage in this housing is totally free !!!
The diameter is the same from the entrance to the water pump...

I send you some pictures of this old manifold, then you can check by yourself.
Was it a special serie or a previous transformation... ???
I examined it but it does not seem that there were any work made.
This part seems to have been casted that way.

Does it come from another car ?
Was it an adaptation for a particular market / country ???

If it's possible to restore it, should I install it on my car to get a better cooling ?
I've heard I shouldn't, it should be worse...

Bonjour de Paris,

Daniel