t-4 jetting

[t-balls400ex]

My friend has 2002 400ex has pro circuit T-4 exhaust and header he doesnt want any holes in airbox and is keeping lid on.Has uni or stock air filter what should he jet it at and what is stock?

[eldoexrider01]

first off the stock jet is 148. if you are gonna use dynojets, then the jet sizes are gauged different than the stock jets. we need to know that your altitude, and which airfilter you are gonna use.

[t-balls400ex]

gonna use a uni and im in st. louis mo.