yes, the point of the return flow from the heater core flows onto the thermostat allowing it to do it thing. You could remove the bock off disc on the thermostat.. that was mentioned when i was researching it... didnt like it lol... i would rather drill holes in that disc to allow the coolant to leak past and flow onto the thermostat
you wanted billit, here ya go
https://www.lojkits.com/products/ls-...r-bypass-block
pretty slick and clean, compact and allows return flow when the heater is blocked off.
In my 99 BMW 528i (ls1 5.7 swap) that has a OE heater valve that blocks flow of coolant unless heater is commanded on. It took a while to figure out why temperatures on the VDO aftermarket gauge would start to climb when a/c on or off at a red light during or at a fast food line. Turn the heater on, temperatures drop within seconds.... the temperature sender is drilled and tapped right on the water pump housing of the LS2 water pump (for reference)
i wound up making one ... turned out nice, a little bigger than lojkits but was cheap.
sharkbite fittings fit real good for the 5/8 and 3/4 coolant hoses... I just brazed them together and painted it black.. almost not even noticeable in my swap.
clint