Nailhead roller lifter I.D

Hello

I have a roller cam and lifters for my Nailhead, but I'm missing 2 of the lifters. Can anyone I.D the manufacturer? Maybe they are from another engine, I don't know, I have never seen lifters like these. One lifter in each pair has a tang on the side anthe other has sort of a double tang that fits over the other one. they are solid lifters with a cup on the top for the pushrod. Any leads on were I can find another pair are welcome.

Thanks,
Magnus

 

Might be Isky I think.

 

Yup there Isky

 

OK that's sounds right. The cam is an Isky RR7000 so this is a Isky set I have... although not complete. But that helps me.

Thanks,
Magnus