Well, is there anything else you could provide that makes a search possible? A name alone is very vague if it's not a really important figure of the past. From what I can find he had
1 victory which might contribute to the lack of information?
So do you have a brief resume? Some pointers what he did after the war? For example what I can basically gather is:
Major Ralph F. Johnson
- CO 319th FS (fighter squardron)
- part of the 325th FG (fighter group)
- flew a P-51D with the serial number 44-15284 #100, it was scrapped September 1945
- the name on the plane was "dusty butt"
- he was the last commanding officer of the 319th FS during WW2, 7 December 1944 – May 1945
A search brought up confusing results. For example that the site of the 319th FS says
he flew the "dusty butt" but the site of the current 325th FG says
dusty butt was the plane of Felix Vidal. Both might be correct however, eventually the name was common.
You might try to:
contact the 325th Fighter Wing historian office though.
You might also be lucky by
getting in touch with the 319th FS directly.
I hope this info helps you getting some results. Feel free to provide further details in the thread as your research progresses as that might help finding what you are looking for.