Re: 73 150hp merc on a 73 gt-150
In my opinion, the GT-150 really isn't a good choice for lots of power. The hull design simply doesn't get the nose up, even with power trim, etc. I just don't think you'll see the kind of performance out of that hull that you think you'll get. The GT-160 (better) or the CV-16 (best) are much better choices.
Regardless, though, the transom, even with a plate, isn't made to handle that much power. It's not a weight issue, it's a torque issue. Unrotted transoms don't pull out where the motor sits - they crack at the sides or at seams. The stresses are transferred outwards. If you see any stress cracks in the motor well or on the deck, that's where it'll fail. A plate won't help that and can actually transfer MORE stress to those stress points...
