Hi, I am a bit confused and hope you can help. My understanding is my jaguar 1966 3.8s is a positive earth. So I changed the leads to the terminals. Once I done that the amp now doesn't sit at 12 o'clock it goes far right. Can anyone give me some advice please. Thank you 

 

Also after starting it I turned it off and took the key out. The ignition light stayed on and there was a bit of smoke from the engine. 

The Mk2 was a positive earth, however, converting it to a negative earth with an alternator is a common change/upgrade, so yours could be either positive or negative.

Do you have an alternator or the original dynamo, or al alternator on the right hand side (as you look in from the front of the car)?

 

 

Hi thanks for responding. I will have a look and see what it has.