two-forty is his speed".  
 
If you could explain what you are talking about, someone may be able to give you some advice on it.
 
I�m not aware of that line being in Jingle Bells either:
 
 
Correcton: I found it! (an obscure verse) from Wikipedia: 
 
Now the ground is white
Go it while you�re young,
Take the girls tonight
and sing this sleighing song;
Just get a bobtailed bay
Two forty as his speed*
Hitch him to an open sleigh
And crack! you�ll take the lead. 
*Two forty refers to a mile in two minutes and forty seconds at the trot, or 22.5 miles per hour. This is a good speed, and suggests the horse should be a Standardbred.
Cheers,
Douglas