piston, bore?

[81 clark racing]

i am thinking about putting a 11.1 comp piston im my 400. it runs awesome now great compression and all so can i just put the 11.1 piston in or do i have to bore it out and redo jetting etc? also do i have to upgrade anything from going from stock comp to 11.1? thanxs steve

[Honda#4]

Find a std bore 11:1 comp piston I recommend JE, umm jetting id maybe up the main or just tweak the A/f screw that may be good but just go out a ride it and see what it needs.