Need advice in repowering or not?

[luisp305]

I have a 1970 20' with a 250 Yamaha Saltwater Series. Boat sits low in the stern, but when on plane it rides really well. What I am afraid is that I can't put two people in the back with 2' seas because I can take in water. I am thinking of repowering to a 130 E-Tec because of the weight. I would like to know if that motor is too small for the boat or if it will be ok and better my ride. Also, does anyone have a 130 that can tell me how fast I will go? Am I making the right choice in going to a lighter motor? This is my first seacraft and I need your professional help. Thanks.