[Nuttyman54]

i'm not familiar w/ the stress analysis tools in Inventor, but you might want to check that it's not just telling you that if you apply uniform pressure along all lateral surfaces you can survive up to 900 lbs before deforming. Looking at weak points, i'd be VERRRY surprised if it could take 900 lbs at the joint.

EDIT: Thought of another thing: are you treating this as one solid object? It occurred to me that the bolts might sheer off before you reach that 900 lb limit....