March Performance Pulleys for FE

[REDSC400]

Hi Guys:

I have been toying with the idea of replacing my current 428 pulleys with the March Performance pulleys. My current pulleys are dark brown adonized billet pulleys as typical from DCE. At present here are the outside (outer edge of Pulley) diameters of my current 3 pulley set.

Crank 3 bolt, one grove - 6" (fits outside of damper)
Water Pump, 4 bolt one grove - 7" (has some Moroso shims)
Alternator, One nut one grove - 2 11/16"

From the looks of my pulley set it is an underdrive (read large) waterpump set, thus maximizing HP at the expense of lower water flow. I am putting ~420 HP at the rear wheels on a chasis dyno with my current setup.

Now, it appears MARCH has two sets of pulleys...

the 1910 Set (Common) which is their "Performance Set" at 5 1/2" crank 6 3/4" water pump and 2 11/16" alternator.

March also has a less common (read special order) 1905 set designed for higher water flow with all pulleys equal with the exception of the water pump pulley, it being only 6" on the 1905 for faster water pump speeds and thus a loss of HP to drive the water pump. I think I would like this set to keep the engine cooler? Your thoughts on this?

Does anyone have experience with either of these two sets of pulleys?

Also, is the diameter that March gives the Outside diameter or the inside grove diameter?

Thanks in Advance.