In Hot Rod, Rod tells his stepfather he wants to save his life with a heart transplant, just to kill him. There is also the common theme of his father telling him he will never be a man because he cannot match his father in a fight. Eventually, Rod (nearly) lands a jump over more buses than Evel Knievel ever jumped, saves his father's life, then beats him up six months later. My theory is that Rod did not become a "man" in the movie, he became a god. His father was right, he could never become a man, but for his final jump he finally managed to call upon several different animal ancestor spirits for their help (before he could only call one) and beats his dad even though he is told his new heart makes him stronger than before and suffered "10-20 broken bones" just six months earlier. His desire to save his father's life just to kill him is him wanting to be a god, to have the power to give and take away at will.