Help with 5.3 LS water pump

[Flysocal]

My crate engine is a 5.3 1999+ vintage. I understand there are 2 different water pumps for these trucks 1999-2004 (what I have) and newer. Not sure when the change happened maybe 2005? Anyway, looking at pics the water neck spout appears different on the newer style pumps which might help me. My radiator hose would be much easier to figure out if I had a newer style pump I think. Also my thermostat housing might be an issue right now. Got a MR gasket swivel housing and its description said 2004+ LS engines. Called Holley and they said I'm good to go but I'm not convinced. When I install the housing in a newer style (corvette) water pump the thermostat and housing bolts up with ease. When I bolt the same Mr gasket swivel thermostat housing into my truck water pump there is about 1/4" thermostat spring compression needed to make it fit. Doesn't seem right to me! Anyway I'm looking for some insight here. Would a newer truck water pump solve both my radiator hose and thermostat problems without creating a couple more? If so, is there any company that sells newer style truck pumps with threaded NPT heater hose hookups? Save me a trip to the machine shop!