Stump Grinder Slant 6 Starter

My neighbor has a slant 6 powered stump grinder that I am trying to get running. It's super cobbled and homemade, but the cool part is that it has a slant 6 engine on it to power it. Only problem is, the starter is so weak, it barely turns the motor over. I am looking to get a high torque mini starter if possible, but the 2 from oriellys the parts guy sold me dont fit. I need a 3 bolt.

Starter Part # 1889100
Starter Head Casting #G1889067

Any idea if there is an equivalent I can use? No idea what the engine is out of, as well as the bellhousing. Maybe just a new standard starter would be enough.

View attachment 1716102852

View attachment 1716102853
I think those direct drive starters are used with a 172-tooth flywheel. If that is the case, then the usual starters for 130/143 tooth flywheel will not interchange. Just something to check.
Also, can you post more pictures of the stump grinder? I like it!