Car's already got a Chevy. So it will be substantially cheaper and easier to keep it that way. It is cheaper to modify. I do not agree you'd get better results...that all depends on the recipe used for the build and the quality of the build. Pontiacs are stout motors...stronger than Chebby's when done right.
Purists will hate you if you put in another Chevy.
Returning it to all Pontiac will cost substantially more money, and depending on the car you MIGHT get some of that money back in increased value. Since it'll still be non-numbers-matching and non-original, you might not. These cars just don't have that much monetary value except for a few concourse and true original examples of specific models.
