Best carb for briggs 10hp

I got an older briggs 10hp (25000 model series) engine from a friend and i was wondering what kind of carb i should use? he put a carb off a briggs 8hp motor on it but it doesnt run the greatest under load. Im thinking of putting a 12hp carb on it, but i dont know if a 12hp carb would bolt up to it or offer any improvement. should i go for the 12 carb or just leave it alone?

Bigger carb would work better- you can adjust them down for proper flow to the motor- you might need to be a lil creative in adapting the carb tho .

You could attempt something similar as a ATV/motorcycle - use the flange that bolts to the motor, then a short piece of radiator hose and bolt the carb up - you might need a stabilizer piece of metal bolted to the motor/chassis to hold the carb steady tho.

Ok then il go for the 12 hp carb. The 8 and 12 carbs have the same bolt spacing so it will fit very nicely.