Turn a small drill press into a Bore/ Hone. Bolt it to the top of your engine block & do your own machining .

When I was young and dumb I once asked the shop teacher if we could bore a block with a drill press
In this shop there was a drill press that handled up to a 4 inch bit which they had and was one heavy bit
The shop teacher just shook his head and said no
Now I suppose if it was possible to jerry rig some sort of boring setup that press could have easily handled it