pretty easy, the center section of both hoods are almost identical, some slight modification was necessary to the header panel to match the ridge but all it took was a little plastic. I have 2 hoods like this and my dad is planning on redoing the other one for his car (he has an 82 elky). We cut out some of the substructure of the hood so the vents are functional as well.

here is a pic before paint, it's easier to see the lines and header panel

yea the orange 69' is my buddies car and the 69' ss is his dad's... Not sure if you noticed but my car does have 69' louvers on the hood

check out the elcamino nice car .. i wouldnt mind a nice 69 elcamino in my driveway right about now