Thermal issues, aka over heating question

[GregWeld]

LS water flow is IN to the motor from the bottom hose towards the thermostat -- and OUT to the radiator at the top hose.

It's easy enough to check flow with a infrared temp gun.... or even using your hand and feel the hoses. Also use the gun to check for temperature DROP from the top (inflow) and bottom (return) --- on in the case of a crossflow radiator -- side to side --- This should drop 20* or so at idle with the fans running.

Use the gun to check front and back of both heads - near the steam vents (I'm assuming your particular LS model has these).

You can also "crack" the seal on these vents (they're O-ringed) one at a time to see if you can hear or see air (steam) vs water flow etc. The temp gun should also show you a temp differential if there is one...

The very first thing I'd do is to use a temp gun to see if the THERMOSTAT and other areas on the block - are reading the SAME as your TEMP gauge.... In fact - I'd do that before I did anything else.