I have a 66 100hp johnson golden meteor. I can't speak to the top end speed but i agree with Bruce that the bad hole shot is troubling. My motor has been an interesting journey. I even had it running on only two cylinders with plug wires being switched. I think it came that way but I can't find the pictures I took to confirm it. If you weren't sure I would go back and check the firing order since you already found some issues you didn't think should have been a problem. It now jumps on plane with just me. Still 4 guys in the back of the boat will make it plow for a while.