Can someone help me estimate my HP

The 318 is a good engine to hop up. Using the commonly available and lesser expensive parts, assuming the heads are not "hogged out" and ruined, I'd say something on the order of 300hp is easy to get out of a daily driver if it's properly done towards performance. If you science it out more, and let us know what the budget is ans if you have power brakes, another 50hp is easy to find.