Most common sign of head gasket gone is air bubbles in expansion tank. And overheating engine.

The radiator got a hole in it when the previous owner had it and lost all its water and about 2 weeks after o got it it overheated on me didnt lose any water or out just got really hot.. thats when i lost boost there after

Unfortunately head gasket is a possibility as pushing excessive boost into a engine can cause the heads to "lift".

Especially without adjusting the fuelling/timing and monitoring the afr .

Scoobs do normally blow combustion into coolant somtimes causing over heating , so a coolant sniff test would probably show hydrocarbons in the water.

When you said it boosted ok if you've got a boost gauge what did it peak at ?

As If it went over 1.2 bar it might have been fuel cut , which might indicate it's not blown the head gasket due to it holding boost

Unfortunately mate that i cant tell you when i first got it i was too scared to look away feom the road lol and now its not connected as i snapped the t peice tryin to get it off when i thort that was the boost issue, but when i noticed i had lost boost it was showing about 7 psi