Just do a simple turn the key and drive it stock stroke 360 with a small carb, even if it makes 400 hp that will be plenty for autocross and track days given the brakes and tires that you have. If you start trying to build some high powered thing or do a gen 3 hemi swap you will be just looking at it sitting the garage for years.
You are not going to win the optima fastest street car shootout with the car if it has 400,500 or 700 horsepower...so build something you can get and drive and not lift the hood for a month.