When i use these assets in Unreal Engine 4 they come in extremely small and i have to enlarge each prop for about a minute in ue4
UE4 uses Unreal Units, with is measured as 1 UU = 1 centimeter.
I use standard units which is in meters. This is a standard used by Unity and Assetforge and lines up to their natural snap settings, but it causes the models to be 1/100th the size in UE4.
You can use Blender or some other 3D modeling package to scale the models 100 times larger and export them, or something like Spin 3D which I think can bulk scale them all at 1 time.