E350Motorcross --- rock on man! Others here can confirm, but with a 2" lift you'll be certainly safe aiming for a 265 tire. (265/75R16.)
(Also --- hey, that it is truly weird....just now checked that PerfSO web link again for your 2" lift kit and the picture of LeadDoggy's van is no longer there. Either it was a glitch on their website that displayed it yesterday, or someone at PerfSO made a change to their page to fix it....or I had one heck of hallucination....)
In any event congrats!