With a score of 340 in the CUET (Common University Entrance Test), your chances of getting a seat in allied courses (such as allied health sciences, biotechnology, or other related fields) will depend on several factors:

1. **Course and University**: Different universities and courses have varying cutoffs. Allied courses might have different cutoff scores compared to mainstream courses like engineering or medicine.

2. **Category**: Your category (e.g., General, SC/ST/OBC) can affect your chances, as some universities offer reserved seats for different categories.

3. **University Demand**: Popular universities with high demand might have higher cutoffs, while others might have lower cutoffs.

4. **Previous Year’s Cutoff**: Checking the previous year's cutoff scores for the specific allied courses and universities you're interested in can give you a better idea of your chances.

To improve your chances, consider looking into multiple universities and their specific allied health science programs. Also, consult the admission guidelines and cutoffs of the universities you're targeting for the most accurate information.