I am with the Air Bubble in the head folks but I have a trick for ya
take a 1litter pop bottle
chop off the bottom
tape bottle to the radiator filler neck.
fill with coolent to top of the bottle.
start truck and let warm up
bubbles with start to bubble out of the radiator
let cool then take off bottle spilling coolant all over
if you do this right it should run cool
this is a trick I used on the trickey 2tc hemi head bubles hide in those all the time
hope this helps
Ken
I hope this helps
PS if you dont have the fan shroud and air dam in place get them I was impressed with the diffarnence