New Exhaust Manifold Arrived

start now cleaning up the threads with a wire brush & soaking with a penetrant. take your time -- since you have a new exhaust manifold don't worry too much about the three bolts that mount the intake/exhaust together, one or more usually break off.

The hardware to the engine the front & back bolt seems to have the most difficulty (interference nut type)
If you have 1/4 drive stuff that will give you more room for the under manifold bolts.
Don't tighten anything too tight until you have the assembly mounted loosely.
Lawrence