Sorry, only just seen this thread.
Turns out the car was a complete lemon, it was a cat C write off, which the previous owner (a member on here) reckons he knew nothing about, even though the claim went through whilst he owned the car
Also turns out it wasn't even a real trans am anyway, just a regular firebird with an engine swap, but they hadn't upraded the cooling system, or the suspension to handle the extra power.
So i ended up flogging it on to an american car collector for a MASSIVE loss. He said he would probably end up breaking it as it was in a bad state.
Oh well, you live and learn, just another reason not to trust people based on face value i suppose.