bush hog chain or solid bar?

[horses2]

I replaced my old bushog with another preowned unit. the one I had used a solid bar to the tailwheel from the A frame. the unit I have now has a chain.

So, what are the advantages and disadvantage of each? it appears the newer models are all "solid" mounted with a frame piece to the rear of the mower.Should I change the chain over to a bar or solid piece?

Also, this unit is apparently a Ford unit made by Bushhog. it has Ford emblems/decals on the deck and has a bushhog model/serial number plate rivited to the deck. the model appears to be S050R, not sure if its a 0 or O.

any help with id for replacement blades? the ones on thier now are about 24.5" overall length, cutting edge 9.25", width 3", offset looks to be about 2".

thanks,