Identify wide Crab Dist. Cap

[Black46]

Hello, I have a 59AB engine with crab distributer. I was at a swap meet recently and a guy had an inexpensive new 1970's? old stock Crab Cap. It looked like what would replace the one on my car. Yesterday I pulled my old cap off and when I put on them on the bench to compare..the one I bought at swap is quite a bit deeper? Please see photos....I have not seen this deeper design...what is this for?? The shape and everything else looks the same..but I dont think the swap meet deep one will work with my rotor etc. So my question is what is this other style for or what is its application? Thank you in advance for your help. Learning every day!


Could this maybe be a Harman Collins duel point distributer cap? I saw a photo of one of those distributers online and it also looked like a deep design cap..