It is. However, if a person this sentence refers to is still alive and kicking, the present perfect tense would be more appropriate:
She has hit many home runs - over 100 (runs).
NB! In written English there must be a punctuation mark between 'runs' and 'over': either a dash (in informal writing) or a colon. Secondly, 'many' used as a determiner is not usual for affirmative sente