Best way to remove stock frame rivets?

[dznucks]

I am about to bag my '69 and i am trying to get myself ready for the install. Looking ahead to the install i am not looking forward to removing the stock frame rivets to install a CPP c-notch and CPP crop center crossmember.

This is my daily driver so I have to work fast and make sure everything goes smoothly since each phase of the install will be limited to weekends. In the past, the best way I have found to removed rivets is with a torch. But I do not have access to a torch now.

So i am wondering what other ways are there other than drilling and grinding? Would an air chisel do any good?

thanks