[RSwank]

There were 3 P-51s lost on 17 July 1944. This one seems the best match to your description.

42-106443 354th FG, 355th FS, MACR 7164, last seen SE of Vire at 15:30. Pilot Thomas Watkins Cannon, Jr. He evaded, "Sheltered in Normandy until liberated".


There were 11 P-47s lost on 30 July, 1944, looks like maybe 10 in France.

42-75413 MACR 7937 for 405th FG, 511th FS, Lt Glessner W Reimer, KIA, struck a tree while strafing at 18:45 2 mi East of Vire on the main highway, so no quite the right time or place. The mission was to dive bomb at Brecey, France.

42-76392 405th FG, 510th FS, MACR 7929 went missing at 19:00 but it was "believed" to be lost south of Avranches. Better time match, but seems wrong place. However,
the body of the pilot, Lt Benjamin F Savage was found at "La Marche"? (probably La Marché, Chavoy, France) and buried in La Cambe. La Cambe is north of St Lo, but La Marche is just north of Avranches. Seems like that would be too far south of St Lo.
They also first dive bombed a bridge near Brecey then went South of Avranches to strafe targets of opportunity.

These seem the "best" matches based on the information you gave.