Ls thermostat housing question

[bigbadcad]

working on a ls swap I have a 2004 5.3 i wanna change the thermosat housing to one that is more straight out water pump. 5.3 Colorado is what i wanted to use but the ID of the thermostat post clamps are to big, a trailblazer has a slight angle and will fit with the upper bolt hole slotted. My question is the trailblazer thermostat is shallow were as the original truck is longer or goes deeper into the water pump.could this be a potential problem with heating and cooling? what have you guys used??