Bigger carb for governed GX390?

[FirePowerMinis]

Is there any thing to gain by swapping to a bigger carb, on a 4000RPM 390, in a heavy kart?
I'm milling the head .100, have done a decent port job, good seat work.
Maybe 1.2-1.3 rockers?
Advance the cam a little?
6-10 degrees more timing?

 

[Newoldstock]

I maybe advance the timing a hair ( I'm thinking maybe 4 deg ).
But not much it will kill your bottom end if over done.

Milling, jetting, minor port work, a decent header and air filter...
These are all good things that will compliment each other and not hurt the bottom end if done correctly.

And I think you could safely bring the RPM a little higher to day 4500

 

[FirePowerMinis]

Thanks