[07cob]

Merv

I would suggest that the plain (non-ribbed) water pump pulley on a standard rotation water pump would be highly ineffective. Unless there was more than 50% contact and a load of tension, I would think it would slip regularly.

The two versions (March product numbers 1670 and 1675) have different diameter crankshaft pulleys. 1675 (the dearer one) is the standard size, while the 1670 version has a smaller crankshaft pulley which will underdrive the waterpump and alternator and subsequently provide about 3 million extra horsepower. My preference is the standard drive.

I will also ditch the old tensioner and will need to look at a tensioner arrangement.

Phil

As it turns out, for different reasons both Merv and I have two water pumps - one in each version - standard and reverse rotation.

Interestingly, I replaced my timing cover recently and the engine was fitted with a standard rotation timing cover with the reverse rotation pump. The plate at the back of the pump stopped water pouring out everywhere and it all seemed to work OK. Looking at it closely, I could see that the water would be somewhat restricted passing through the timing cover, but it wasn't enough to worry. Regardless, I replaced the equipment as it was as the cooling is fine. Looks now like I might use the standard pump with some fancy pulleys.

Cheers

Geof