273 to 340 swap

Daves66V
I looked at my 66 Dart 273, p/s installation( which is stock), and it is exactley the same as on my 69 B-Cuda. So if your Valiant is still stock , you will have no problem. Go with the 273 stuff. My 66 Dart has the same kind of alt mounting bracket as in you pic, that might have to be altered.

Good Luck Dave C.