I found I could burp the LS1 cooling system better/easier/quicker by connecting a 5 ft (or so) length clear tube to the front cross-over pipe, the other end of the tube going into a bucket/bottle on the ground;
I can see air/vapour coming out, and when I see only coolant then I know I'm done, remove the clear tube and connect the TB[-bypass] hose, top up radiator and install cap.
Now, how do I prevent a whole big glop of coolant from flopping out the radiator neck just before the coolant level goes down (...it's just like it threw up at me...)...?
I even tried to allow for this by filling not-so-high, but the level just kept coming up and then threw up everywhere;
should I have put the cap on before it reached the top of the radiator neck (but then I would still have to add coolant)...?
The Service Manual says to open the bleeder on the thermostat housing.... that seems to be carry-on from when the TS was on top; I don't see a bleeder on mine (and it wouldn't work because the TS is down low);
Yeh, I had to replace the heater core, it was fogging my windscreen/windshield with coolant.