Ok so upon talking to the friend I got the engine from, he did swap the upper to one from a 4 cyl after hitting a stump at wot... I had known that before but thought he said the ratio stayed the same.... now he tells me that it was higher before (1.65)
anyhow, FWIW I tried both 1.5 and 1.98 with various props on the heavy boat and all around performance was much better with the lower gear about 3 mph on top end at the same rpm and amazing acceleration..... she jumped out of the hole better than many smaller boats with more power