The burritos have 10*120=<<10*120=1200>>1200 calories
That means he gets 1200/6=<<1200/6=200>>200 calories per dollar
The burgers get 5*400=<<5*400=2000>>2000 calories
So he gets 2000/8=<<2000/8=250>>250 calories per dollar
So he gets 250-200=<<250-200=50>>50 more calories per dollar from the burgers
#### 50