gmore

Bought an inop 08 Z06 with engine out(being built) that I'm gathering parts for. According to carfax, it had an engine swap in 09, so I spent some time researching part changes from 08-09, in case something else may have been swapped at that time(wp is an 08). Other than hoses, thermostat and housing(which I'm replacing regardless), all else seems compatible(same belts) and the 09 WP is about $30 cheaper and I'd have to assume is some type of improvement?
Any reason to not do this?

double06

The 2009 may have some improvements I have had both on the 2009 the water passages seem to be bigger but one thing is the top outlet is on the drivers side in the 2009+ versus passenger side in earlier years. I like it on drivers side (2009+) as the hot water hose is not under the air intake hose. Also makes it easier getting belts on.

HOXXOH

The water pump change was made to accommodate the supercharger location on the ZR1.

EnginerdVT

Something else to think about is that the 09+ WP has a much narrower pulley than the earlier models. I'm doing a 10-rib supercharger build and the 09+ WP would not work with my setup since the pulley is too narrow. May not apply here and I don't know the other passage/flow changes that were made.

double06

When I switched over I did a comparision. The water intake port passage is bigger on the 2009 and the thermostat diameter also changed slightly. The thermostats do not interchange between pumps.

gmore

No plans for FI, but that does explain the extra holes near the center mounting holes. FWIW, in add'n to being $30 less, the ACDelco 09+ includes the thermostat housing and places like Rockauto offer a $14 180-degree thermostat, whereas the housing is add'l for the -08s with only 187-degree as an option. I've read about 'some' 09+ coming stock with a 180 thermos but others disputing it?
I think I'm sold on 09+.