I would think by removing .125 off your cylinder, the head deck will be pretty thin & cause head gasket sealing problems, esp w/a lot of Nitrous.
A 194 valve is too big for a 194 head, the chamber would be shrouded the valve too much,plus if you try & cut a seat for a 194 intake valve ,you will probably go into the water jacket.
If I remember correctly, I cut my 1.94 valve down to a 1.90
I would just run the 250 crank, unless you are trying to run in a certain class.
MBHD