The ring gear diameter is 10.5" vs a D60 that is 9.75". Strength is much higher in a 70 than a 60. Haven't weighed both housings yet, but I don't see the 70 being that much of an overwhelming increase. Yeah, it was real heavy, until I pulled the hubs, rotors, axles out. I will weigh it after I cut it to proper length, for comparison. I'm not breaking anything, but I need to replace my existing housing and am checking different options. Gear ratio's are available from 4.10 up to 7.17. I don't think a "Pro" style gear will be necessary.