interesting you say they came with a babbit bearing. i may have couple different pictures of that same rod you might of had back in the day depending what type of motor it was.
this one was made for a block that came with a oil pump.
as you can see it has no dipper.
View attachment 272032
View attachment 272033
this one has the dipper on it.
View attachment 272034
arc does make a .875 babbit bearing and little bit luck with some measurements from the tecumseh and maybe little finesse with machine work that bearing might work? and i'm sure you could use the arc rod bolts they sell in different lengths. all this might help you local machinist make them little bit easier. i would interested in one if you guy decides to change his mind.
i like to see one of these little guys turn 7000+ rpm's ....between my legs....lol
demon72 you might like to see this build i did couple years. you could say it's a one off only build done like this....
https://www.oldminibikes.com/forum/index.php?threads/hs-40-build.161335/