I don't have much to add but I am going through this right now in my 1965 C10. A remanufactured 230 or 250 from OReilly was about $1600, required a core. and came with a nice warranty. The 250 would be my choice and they look the same on the outside.

I ended up buying a recently rebuilt 230ci from a fellow Stovebolter who did a V8 SBC swap.

The 3 speed and original bell will bolt up to a SBC and you just re-use the engine perches and get new motor mounts. Just be aware that tall valve covers MIGHT interfere with the firewall. Also, the distributor cab interfere too if it is the taller HEI version.

I love the uniqueness of my inline 6 and for a daily driver I am totally happy.