1 7/8 headers

I have a RB in my 71 Demon and it has 2 inch TTI's. I'd go with the 1 3/4. You'll have more room..As TTI doesn't make an 1 7/8. I'd go with the 1 3/4. The 2 inch are very tight in an A body.
I have used both. Currently have 1 3/4" and sold the 2" as they were miserable to work with. They fit great once one, but man I hated those things. I think the 1 3/4" could be hurting my combo some so was trying to find something a little bigger. May just have to make a set myself, but not sure if I have the patience for that.