Pinion pilot bearing replacement

[larry/Texas]

I am changing my '33 ring and pinion to a 3.54. I am also replacing the pinion pilot bearing and retainer. I do not have and can not find the oval head tubular head rivets (63397-S). They are 3/16" X 11/16". They are hollow for about the last 3/16".

What are people using in place of the rivets? I can find pop rivets but am concerned about them. Any comments or recommendation would be appreciated.

Thanks