The /æ/ vowel is spelled <a> followed by two consonants or by one consonant in a monosyllable. The /ʊə/ diphthong is spelled <our> or <ure> in lured.
This contrast is between a short vowel and a diphthong well separated in the mouth, so it should cause no problems.
bass bourse dally dourly gad gourd gads gourds harry houri harries houris lad lured mad moored pally poorly