Is there a particular reason why the pulley size changed?

Is there any difference in pumping efficiency between the short and long snout pumps?

On 2 v8 tonners im playing with they have a pulley very close to 1:1 with the balancer pulley.

They both look like long snout pumps, pulley seems to be around 150mm diameter

One is HZ, the other is WB.

I have a short snout pump (genuine holden, VT i think) on my stroked 308, and the pulley im using is smaller than the above mentioned, (could be hz sedan pulley, i dug it out of the shed years ago)

it measures around 138mm.

I like the idea of slowing the water pump down on an engine that idles at 1100rpm, spends most of its time cruising between 3000/3800 rpm and turns to 6700.

Are there any downsides to this?

cheers

11.38@117

Edited by user Friday, 8 January 2010 5:24:48 AM(UTC)  | Reason: Not specified

cheers doc.

I might just bung on the larger pulley and see what happens, i imagine it will get plenty of water flow at my rpm parameters without the overdriven pump, and the belt driven fan is long gone.

11.38@117