Alpha 1 ss water pump number?
 

Going off memory from my old SS...... It's a Gen 1 Alpha water pump setup.

Correct.

Note: The plastic tube that is re-used is shorter and in the pocket in upper ha;f that has the upper brass tube, has a gasket and plate that is roughly half open vs the regular Alpha having it fully open.

Oh, you'll need a different set off muff's if you start boat out of water. Give me a bit to remember/find where I bought them. I do remember it was from the guy who makes all the Merc racing ones.

It is best to buy the complete kit -- the lower base and all - the kits can be bought 4 or 5 different ways - I would buy the complete kit as that is cheaper then buy say half pieced out as a kit. Let me know if you need help with that - have to watch out which kit you buy cause the base can be different and so is the base O ring.

Word of warning - the Alpha 1 impeller is the VERY short vane impeller -- with that said it performs as a high water pressure - less water flow volume impeller than a GEN 2 Alpha impeller. So the composition of that impeller is made with harder compounds --- Do not buy one that has been sitting on the shelf for a year or 2. The impeller becomes harder / stiffer sitting over time even on the shelf and then inreturn flows even less volume of water and less water pressure.

Years ago my shop was part of testing impellers for a aftermarket marine company. One of the tests was water volume output in which is very important. . We tested Globe - Merc - Jabsco - Johnson - Sherwood - And many China and even ones made in Taiwan and Italy brand impellers. Italy brands did fairly well but the best were OMC OEM and Merc OEM impellers both made in the USA.

This Alpha 1 impeller needs to be changed MAX 2 years but I really recommend ever year for that one especially if the boat did not get used very much within that year..

I remember reading the half plate was designed to lower water pressure to an acceptable level due to the LWP of the SS lower.