K-Frame

Good day folks,

my son recently purchased a 74 Dodge Dart “Swinger” long story short we rebuilt the front end to find the frame was bent on both sides and the K-Member is mangled pretty bad. I am looking for a K-Frame to put in his car. I am REALLY new to A-Body cars and do not understand entirely all of the different options. The car is a 318/V8 car. Currently we are not looking to do a swap for a BB and not making huge HP. Any help would be greatly appreciated!