Doing a vtec oil pump upgrade on my LS Vtec turbo project and im planning on getting a Cicuitworx oil pump drive gear my problem is on their site they sell a 80mm and a 84mm gear thet say the 84mm is for the JDM i dont understand what this is supposed to mean i thought they all used the same gear

I would just run a brand new oem vtec oil pump. Just about everyone will tell you to run nothing but the oem oil pump