Different size torque converter knob 170 vs 225?!? Are you kidding me?

A custom torque convertor can be built. Years ago it was Stegalls Transmission that did this locally. J.P. Stegall was the torque convertor man around here. Those were the good ol' days.
I don't know where I would find that service today, Google I guess, call the local trans shops, etc...
On a positive note... If/when you go to put the later 225 back in, a little bushing poked into that crank makes the custom torque convertor still fit.