Engine swap 4.3L to 4.5L

[fester]

Howdy forum..

Looking to swap the engine in a 2001 Maxum 1800sr from a 4.3L to 4.5L however the dealer is not comfortable putting in a 250HP. Dealer mentioned the gear ratio of the A1G2 wouldnt be able to handle it.. Its 1.8 so thats fine.. Then mentioned A1G2 wouldnt be able to handle the extra HP.. Said that was BS as its rated to 300HP.. Then said the hull wont be able to handle it and unfortunately I dont have any documentation or anything solid to say it can..

Does anyone know what I can say here? I rang mercruiser support and they said 50hp doesnt make that much of a difference and should be fine.. however recommended I contact the boat manufacturer

Any advice would be very much appreciated.