Has there ever been a 7–4 in MLS?

Yes, 1 time.

The only time: May 5, 1998, LA Galaxy beat Colorado Rapids (LA Galaxy 7–4 Colorado Rapids).

Nearby scores

1. 8–3 Never
2. 8–4 Never
3. 8–5 Never
4. 7–3 Never
5. 7–4 1 time
6. 7–5 Never
7. 6–3 6 times
8. 6–4 4 times
9. 6–5 Never