If you are wondering why I used *s instead of some letters - it's because this Site keeps blocking my response stating I'm using "inappropriate" language. I have NO idea what it is.
I'm not sure what you're calling a "smoke scr*w." Some Stanadyne/Roosamaster pumps have "torque screw." I doubt the Ford 172 has it - but cannot say for sure. Regardless, ALL Stanadyne/Roosamaster pumps have a scr*w you can turn in to increase max. fuel delivery. That being said, diesels without turbos rarely respond very much except for making extra smoke. All depends on how "detuned" it was when it left the factory.
The Ford 172 diesel makes max 41 horse at 2200 RPM . A gas 172 makes 47 horse at 2200 RPM. Gas engines always make more power then equal bore and stroked diesels (equally aspirated) and 41 horse sounds like it's already set pretty high in fuel delivery. You might squeak 1 or 2 more horse out of it along with some smoke. Can't say I've tried.