you want the least bores as possible. if your stock cylinders are still stock get them ported then bored. you only need to get it bored as least as you can. another words if your 10 over and your mechanist says you need to go 20 then do it. if he says 30 over then do that. dont go 10 to 80 over. thats like throwing money away but you want the port job first then bore. that will save you about $90 or so.
stock carbs are 26mm.