my stock gear was a 323 i changed it to a 373 the only reason i bought the tuner to set gear ratio to fix my speedo

i just bought a i 1000 and can not find where to chance my gear ratio from stock to 373 ..and also its only showing 87 tune or diablo tune any help would be great thanks

i just bought the intune for my 2006 silverado i dont see the settings to change for a gear change