Technical T5 shifter fastener question

I just finished rebuilding the T5 for my falcon along with the s10 tailshaft conversion. I didnt have the s10 shifter so I built one from the mustang shifter and did a short throw mod. question I have is what fasteners can I use to put the pieces back together. I drilled out the original rivets , what does one usually use to put these back together ?

 

I dont know, Rocco. But I do have some questions about the S10 mod, if you're up for it.

 

It has been 10 years since I did mine but as I recall I used grade 8 socket head cap screws and nyloc nuts.