Some have claimed that the B. C. Great Isaiah scroll of the Dead Sea Scrolls is identical to the Hebrew Masoretic Text. Overall generally the Great Isaiah scroll has the same Hebrew text, but it is not 100% identical.
KJV defender Douglas Somerset wrote: “The ‘Great Isaiah scroll’ (Isaiah A or 1QIsa) has a broadly Masoretic consonantal text but it differs from Masoretic in about 2,600 places” (Hooper, It Is Written, p. 244). Douglas Somerset maintained that Isaiah A “has much fuller spelling (which is of little consequence); adds or omits occasional words; shows some variation of singular/plural; omits verses 2:9b and 2:10; gives a shortened version of verse 40:7” (Ibid.). Yosef Ofer wrote: “Comparing the text of the first Isaiah scroll to that of the Masoretic text, we find no less than 14 differences of various kinds” (Masora on Scripture, p. 171).
Douglas Somerset wrote: “Much closer to the Masoretic consonantal text of Isaiah is the incomplete Isaiah B (1QIsb). For example, ignoring spellings, there are four differences in Isaiah 53, including one extra word in the Hebrew. That occurs in v. 11, where the word ‘light’ is added to give, ‘he shall give light.’ Isaiah A and the Septuagint also have the word ‘light’” (Hooper, It Is Written, p. 245). Yosef Ofer wrote: “The version of the second Isaiah scroll is closer to that of the Masoretic text, and in this sample [Isaiah 58:4-6] there are only nine differences between the two” (Masora, p. 171).