If any one in interested in improving there Bombi's gearing I took out the 589 gears out of my Bombi and put in 427 gears they are just a standard rotation Dana 44. Its a completely changed machine lots of power you in lower gears and it does 30MPH at 4500 rpm I got the gears from summit racing $150
And its not a big job just make sure you time the gears when you put the diff back together
And its not a big job just make sure you time the gears when you put the diff back together