[Roadsters] Distributor cap question

[Fairlady]

I purchased an EI about 5 years ago from GB, it's great. BUT I recently
cracked my distributor cap, I thought no problem I'll just take one off of
my other 2000s. NO GO, both of my other caps are smaller than the one on my
EI.

The EI has fea1440 on the top piece

I can't seem to find any information about different distributors. 

Can anyone suggest anything? 

 

Chas