I'm able to dead lift 270 at 5 reps without straps, after that I need to add straps to get to 400. How much more should I be able to hold if I used chalk?
I'm not sure how much more chalk will let you hold. Anecdotally, on my last working set (when my hands are the sweatiest) I can do maybe 3 reps at a given weight without chalk, and get past 10 with chalk. It's a pretty dramatic difference.