sr heater lines- does feed/return matter?

[K_never_broke_again]

Hey guys, Im setting up heater core lines on my sr/240sx swap, but Im not sure which way to route them. I've done a good deal of research on it, and I've heard some people say it doesn't matter which way you route the lines into the heater core. Is this true? I don't really know how this could be the case because the oem heater line valve when closed would cut off the coolant going to the turbo, at least thats my understanding of it. If anyone has any knowledge on this it would be great to know. Right now i have my lines set up like this- top of heater core line(with oem cable valve) going to the hardline that ends under/inside the intake manifold- and long hardline(with turbo coolant line) which wraps around the back of the engine looping back to the lower heater core port. Based on a few pics i've seen i think this is wrong, but let me know