Im new to the forums and a noob on engine mods. I have a 78 miller 20 ft mini cruiser with the bone stock 460 with log manifilfst. I believe top speed is 54 @ 4400rmp. She's a well built full stringer boat and a bit heavy. Besides an intake manifold electronic ignition speed grate and diverter, what will she need to reach 70? .I would be happy with an honest 65. Thx!