It’s difficult to predict according to marks because it varies a lot from year to year as well as shfits - morning or afternoon. What is more a constant parameter is percentile. And you need 99.5 percentile to be in AIIMS Delhi. That means you need to score higher that 99.5% of candidates.

The year I got admitted to AIIMS in 16, it was 136 for morning shift and 128 for afternoon how far I remember. You can take 140-150+ as the safe score.