||I've fixed a couple TT's that lost all coolant due to water pump or rad failure. It's likely not head gasket, it is likely overheated pistons that have pinched the rings.
Both of the ones I fixed had totally killed the engine. No cylinder had compression over 80psi, cylinder walls were scuffed and the pistons were trash. The heads were warped on the one, OK on the other.
Honestly, if you have very low compression on all cylinders, I would look for another engine core to rebuild or an drop-in replacement.