66 Plymouth Valiant 100 Parts Interchange

a 66 is a one off year when it comes to rear bumpers, more square than a 64-65. Hood doesnt have the spine the 65 has (?) rear "backlight" is 64-66 same. slant 6 had the same K, you just need the V8 mounts and brackets and the drop center link. I would consider keeping the 6 in there. Many upsides to an original 6 as in exhaust and originality. You can build the 6 up too as these cars are pretty light to make a quick ride.