The King James New Testament comes from the “Textus Receptus”, all other English New Testaments come from a text by Westcott & Hort.
If you have a Bible that does not have 1 John 5:7 in it, then your bible was made using the Westcott & Hort Greek New Testament, which means Westcott & Hort removed parts of the Bible that are in the Textus Receptus.
This does not mean that I believe the King James Bible is the true word of God, the King James is not 100% truth, no English Bible is 100% truth, because Greek cannot be translated correctly to English.
The Textus Receptus was written before the Westcott & Hort, now if the Westcott and Hort text is missing verses that are in the Textus Receptus, then how can the teaching that says, “the English Bible is 100% truth”, be true, when one English translation has verses missing, that are in the King James?
1 John 5:7 KJV – For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
1 John 5:7 NASB – For there are three that testify:
The King James Bible definitely has errors in it, Titus 2:13 is translated wrong in the King James, here is a link to my post entitled “The English Bible Isn’t The True Word Of God”, that will explain more about the King James translation of Titus 2:13 https://bornfromabove7.wordpress.com/2014/08/29/the-english-bible-isnt-the-true-word-of-god/