I would have kept talking to my friend if it weren't supper time.
If I didn't have to eat dinner, I would have just kept chatting on the phone with my friend.
「夕飯の時間が来なければ」と言うより、次のように表現した方が自然な感じで良いでしょう。
ーI would have kept talking to my friend if it weren't supper time.
「夕飯の時間じゃなかったら、友達とずっと話し続けただろう」
ーIf I didn't have to eat dinner, I would have just kept chatting on the phone with my friend.
「夕飯を食べなくても良かったら、友達と電話でずっと話し続けてただろう」
ご参考まで！
カナダ 
