New carb for dr 135

hey guys ,

 

i'm new here and i would like  to ask a question.

i have a p80x with a dr 135 cilinder kit.

i'm need to buy a new carburator  ,so i was thinking of a delorto SI24/24d instead of the standard SI20/20d.

do i need to ajust the the hole in my carter for this or can i just fit it on there as it is?

also will it help with the spitback of fuel that is comming out of my current carburator?

greets rastadude