Lucas electrical systems- - - - -that's why the Brits drink warm beer - - - -they've got Lucas refrigerators!
Hey, just a minute.... it was apparently running fine till the man installed an aftermarket AMERICAN ignition sysyem!
We drink warm beer cos we like the flavour of the stuff BTW; difficult when your taste buds 've just been nuked by iced swamp water!
My experience of MG's is very limited, but I wouldn't be surprised if the distributor plate is grounding as suggested above.
