Hi max
once again for your, A a little more time has passed and a deep dive on the web the sprint 375 engine is a 1995 model so deffinately a replacement.
It had its first test dig today 18/09 and it tills like a demon. As far as the depth tool i managed to scale from the same drawing and getting dimensions off it ( boilermaker by trade with a bit of machinist thrown in to get myself into trouble. from what i can remember the we had on the farm when i was a teen the ripper helped to put back pressure on the tiller so that it didn't pull. Sandy soil here in Perth dont really need it as you have to push .the unit was given to me so semi restoring was a cheaper option as well as saving and using some Australian history. i trying to work out how to attach pics.
regards
Philmore