I am starting to do a some looking for a combine to replace our 1440 probably for next year. I wanted to step to a 1660 but I have noticed that 1680 can be had for the same price or maybe a little less. so now for my questions. First of how much of a capacity difference is there between the 3 sizes? Our 1440 is a very early and it seems to be maxed out in corn about 3.5mph before we start to run out of power. Our main crop is corn and we have around a 110-130bpa average. We also grow some wheat (50bpa) and oats (50bpa). We are currently running a 6rn head and a 16.5 ft 820 flex head. I would like to step up to an 8 row in the future and we need to replace the 820 anyway. Our ground would support a 20ft head maybe a 25ft max because our ground is pretty rolling. Will a 1660 handle an 8rn head and a 25ft head? How much better would a 1680 handle it? Could we even go fast enough to keep the 1680 full? How much bigger is a 1680 physically compared to a 1660? I know it will have some heavier components but is it taller or wider? Is there anything specific to a 1680 that I need to look out for? Thanks for the tips.