Okay I have a stock 79 5.0 motor. I am pretty sure I'm getting a crane energizer cam. I have these 3 choices. A 272 duration the part number on that at summit is crn-130052, theres a 284 duration the part number on that is crn-130062 and then there is a 278 durtion the part number on that is crn-130092. I'm unsure what would be best for my car. I just know I want the most possible power! You guys are always helpful so...suggestions?