What size Mikuni should I run on a 14 kohler? 440cc

Or would it be a waste of money and I should just drill our the jets on the stock carb?

I am planning to port/polish the head, maybe shave the head and advance the timing a little if I get ambitious, remove the governor, add a racing header and silencer.

this one lol

I need one like that for my weed whacker:lol:

Basically! hahahahaha
I've been looking at 24-34mm almost all of the adapters come with a 60mm bolt pattern but my head has a 52.5mm bolt pattern.

I'm thinking about buying the adapter and seeing if I can tweak it enough to fit just to see if the whole mikuni project is doable without a ton of hassle.

Just curious as to why you would want to put a Mikuni on the Kohler? I can understand on the Briggs engines because they have terrible hesitation coming off idle sometimes causing the engine to kill if you throttle up too fast, but I was under the impression that the Kohler's had no such problem (never owned one on a mud motor).

No, mine doesn't have that problem.
I just want to do some mods to make the engine breathe better. I want to be able to flow enough air and fuel to feed it after I do. Maybe the stock carb can handle the extra air and I can just drill out the stock jet.....

Maybe I should just scrap the Kohler altogether and build a 440cc honda clone that will take all the GX390 performance parts.