The person you need to contact is Clensing, or Clansing, can't remember for sure how its spelled, he's a member of HEF and he and/or his family have done a few of those conversions over the years, seen the machines myself so I know they've done them. They used L10 cummins out of trucks for their conversions if I recall correctly. Give him a PM and see if you can get ahold of him.
If you can find a 20H to get bell housing numbers to compare, along with torque converter numbers and measurements, most of the work has already been done for you, then all you need to do is copy those machines. I've repowered several machines over the years but not a dresser dozer, if you can get those measurements and numbers off another machine, 90% of the work is done, then its just a matter of taking plenty of pictures and jotting down measurements and then you know it'll work. The 20H ran a L10 from the factory in them, to put a Detroit or something else in one, you have to do all the work to figure out everything to make it work, not something I'd recommend unless you have plenty of time and parts at your disposal. Its so much easier to copy everything that's already been done before, to talk to someone who's done it, is priceless in my opinion, especially with all the issues you'll encounter along the way. Just my two cents worth and best of luck.
