Vintage dist cap question

Greetings from Cartoogechaye NC ,
Recently bought a 51 GMC 350 and eyeing some tune up parts on ebay can someone educate me on this applicable cap it has threads down im br*** part where wire end would go ?? What type adapters etc are needed to put a conventional wire in these ? Thanks

 

Not sure, hopefully an experienced answer comes along. In the meantime, take a look at this selection.
https://tonsperformance.com/

 

Is there a spike down in there?

 

I will get a better photo tomorrow
I just never seen threads in cap but could have been for severe duty applications etc
Im going to use them if I have to drill them out so conventional plug wire attaches

 

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Have bought from them before great company with old school inventory supplies
They sale on Amazon also

 

Might have had thread-on caps or covers. They would have to be pretty thin for spacing though.
The ones with a threaded spike were for solid core wires.

 

Was that cap part of a military setup. GMC built lots of military army truck stuff with the 6cyl. Some other mfgrs such as my Willys Jeep used waterproof ignition systems that were also 24 volt. Don't have the cap and wires available to look at right now since they are in storage. I do think you should look at military.....waterproof.....24volt. Have fun

 

If there is a Needle / Nail point in middle of Br*** you slide point cap boot up wire , then stick wire into b*** then slide boot over poll ..

If No Needle / Nail point you would use one of the 3 in pics
There are other styles, look for othere in mid 60's & older Farm tractor's

 

Lucas used something similar. They had an acorn nut and a br*** washer that you splayed the copper HT core over.

 

First you need to know if the cap fits your current distributor diameter and has the proper notch to keep it from moving. Then you need to know or somehow has the correct depth for the rotor to be inline with the contacts in the cap and do not touch.

I have had many caps with a screw in the female end and I used real wire wires and turned them into the screw. The rubber cap sealed them from moisture. They were all on vintage 20’s-40’s motorcycles .