1966 225 slant 6 Motor

Can I use that photo in my ad ?

sure, if that helps, go for it.
Can I ask, why are you looking for a '66 slant only. The slants cross change over many years. One can get into the
crank register size, (pre and post '67) but there are work arounds for that.
I'm bring a 1966 car back to it's original self . I am removing the 1965 motor that is now in it ,using the 65 motor in a 65 Barracuda and replacing it with a 66 in the 66 car.I have other slants but not the correct one for the year