Have a look at the rods and jets between the two. numbers on the side. If they are the same flow rating...the jet/rod combo would be the difference. You can adjust the plastic arm inside to put the tapered rods lower, leaner, into the jets. iirr.
I used to play with those as a teenager on my slant. Once i figured out carburetors a little later.. i realized what i could have had...really knowing what to have changed/adjusted.
