Vintage Air Gen IV heater fittings

[snappytravis]

Just a little confused on this one, I am working on gen IV heater hoses I see that va sells one hose that goes from 3/4 to 5/8 it seems like, I have two fittings for the heater hoses off the heater box, They are both the same thread. I have a ls3 with the stock press in nipple fittings. What is the best way to run my heater hoses, Tap the water pump? Then what should I use on the VA Gen IV for the heater hose fittings.
Thanks