The scores are exactly equivalent per the official concordance tables - https://www.act.org/content/dam/act/unsecured/documents/ACT-SAT-Concordance-Tables.pdf
I would agree that sending the SAT is probably better as an engineering applicant, based on the individual component scores. A M780 concords to a M35 and probably influences engineering admission decisions more than EBRW/S/R/E
I see no value in deleting an identical ACT score.