05 LLY still burning coolant

I have a 05 lly and I just replaced the head gaskets and when I was doing it both heads were resurfaced, valve job, new thermostats and radiator cap and I flushed the system. The radiator hose will kind of suck shut but then it will go right back to normal after a few minutes and it's not hard. It's not overheating it's running at its normal temp. Also have a egr delete. I got to work this morning let the truck sit for about 10 minutes and took of the radiator cap and there was no pressure. Anyone have any other ideas?

Check the heater hoses as they relate to the EGR delete. It can be difficult to get a good seal on these with conventional clamps.

Also consider a pressure tester.