will 65 front clip fit 66 Valiant ?

It works fine but take a picture of a 65 and a picture of a 66 and put them overlapping. A 64/65 is more rounded in the front like the bumpers and the tops of fenders. Where the back of a 66 is more square with the bumpers and the quarters are more square, just a thought.

I put a 65 Barracuda Front end on a 65 Signet, looks like a Notchback Barracuda now. The only difference in wiring for me was the turn signals, i think all main light harness' are the same 64-66, its just the difference from the signal harness's from the radiator support to the turn signal itself.

hope it helps.