Blown head gasket??

[redsand]

Okay need some opinions/thoughts before I tear this car apart. I am not an engine/cooling expert at all...do more wiring/interior etc.

403 olds 79 trans am. newer rebuild. Customer drove the car without issues. Throw a belt on the highway and continued to drive for about 12 minutes, he could not tell me how hot it got. When he shut it down, a minute later he said he heard a boom. It actually blew the upper radiator off the rad. Not the hose the actual metal brased connector.....stock overflow....It built a hell of a lot of pressure or I had a bad cap.....so I got the car back and replaced with all be-cool rad/fan/overflow...ran great, burped properly stuck around 180....Customer got the car back drove it for about 2 weeks and now this morning white smoke is coming out the tailpipes and the car gets to 220 in about 5 minutes...I told him to let it cool down and check the rad fluid level...My guess is that I am still having some kind of pressure issue and I lost a ton of fluid out of the overflow and basically running dry again.....So I have a pretty good feeling that the head gasket are toast with the smoke but wanted to bounce if off of you guys? He also said when he shut it down he heard a bunch of gurgling?

1) Any idea what might have caused the pressue issue prior to the be cool instal? would a threw the belt would the 12 minutes of hell have started the distruction with the pressue / head gasket
2)would a blown headgasket create the pressure and gurgling he is hearing with the be-cool setup.
3) I there an easy way to tell blown head gasket before I have it delivered back from detroit that he can check?

any help would be greatly appreciated.