There is no direct conversion between ACT English and SAT English scores. However, you can estimate your SAT English score based on your ACT English score using a conversion chart. Here is one such chart:
ACT English Score | SAT English Score
-------------------|-------------------
1 | 320-350
18 | 420-440
25 | 500-520
29 | 560-580
32 | 600-620
36 | 680-700