Its because of the nats crap.
I lifted a full loom ecu keys chip engine transponder and such from a sport+ in running condition.
However once fitted to the new chassis it wouldnt work.
At all.
So i swapped the cylinder head for a dizzy one off a cg13 ad a whole new loom ecu chip transponder key etc so that it could be run on that instead.
Plus with the cg13 head... carbs are an easier option.