I have a carbon fiber hood that I wanted to reclear that has some deep rock chips do I sand the hood with an orbital or should I use a sanding block?

Well, a first question might be....how are you going to deal with deep rock chips on this? If you are a "newbie" to this sort of work a hand block wet sandpaper method would be the safest for not "showing" orbital marks.

Orbital and 800 grit will work fine,

if those chips are into the carbon fiber you can use some clear epoxy like DP100 to fill them in and sand smooth, you do have to be careful not to sand to the fibers around the hard epoxy though... post a few pics lets see the condition of this hood before you follow my advice. i want to make sure your clear isn't ate away to much.

https://www.uline.com/BL_121/3M-Epoxy-A ... lsrc=aw.ds