Originally Posted by Martinnhs12
I took it to a mechanic, my Auto Tech teacher, and he said the gasket is blown and possibly the the cylinder head is cracked.
Firstly, welcome to GM Forum! Thanks for entrusting us to help you fix your motor.
Now, I'm no expert on the Series I, but from what I've read during my years here, it'* pretty rare that you blow a head gasket or damage a head on any 3800. (Of course, given extreme heat, any gasket will fail. Been there, done that on a couple of easy-to-reach gaskets.)
Cast-iron heads don't easily warp like the more common aluminum ones. But since you can hear air, I'll assume you're failing the compression test, so you may have a damaged head gasket, a warped valve, or maybe a couple blown valve seals.
You can either troubleshoot, tear it down for inspection, or grab the nearest short or long block and go at it. Whichever route you go, you'll find plenty of knowledgeable members here. Keep us updated.