The steerer threads are very likely 25mm x 1mm pitch and not 1" x 24 t.p.i. which will mean a french headset. If so, the stem is 22mm diameter and not 7/8". You can get English threaded forks and headset. Unless you are into old peugeots (I like 'em) or the frame is special and high quality, it may be easier to get another old frame with English threads.
The steerer threads are very likely 25mm x 1mm pitch and not 1" x 24 t.p.i. which will mean a french headset. If so, the stem is 22mm diameter and not 7/8". You can get English threaded forks and headset. Unless you are into old peugeots (I like 'em) or the frame is special and high quality, it may be easier to get another old frame with English threads.