why not just buy the autoloc kit?

 

Depends upong the coil - if it is a standard "old" style coil any point set will contain one and you may be able to get one from a Autoparts store - they are pretty much all the same with some different mounting brackets - any size should work ok but one matched for that coil you are using would be best. If you know what the coil was used in i.e. car or motorcycle? It would help at the Parts store. I think they are a few microfarads at 300-400 volts.