There have been MANY mentions of a box blade as additional weight,,
My 6 foot box blade is so light, I can pick up one end.
Replacing that weight with a steel bar would be easy.
If you want REAL weight, get something like the weights I bought for a couple hundred dollars,,
(Maybe it was only $100,,!??)
It is the rear ballast off of a John Deere track loader a guy was scrapping,,
I haven't tried it, yet, but, I doubt that my 584 IH front end loader could lift the weight set.
I can lift it with the 3 point hitch,,