Impressive. That's a good amount of pull ups. With the capability of doing that many reps, I'd start incorporating weighted pull ups if you haven't yet.
Another thing one can do, as per Arnold.
Divide the Pullup, into 2 different parts. The Initial Pull/Halfway, and Halfway, to the Top of the movement.
And he used weights. 6-8 reps.
Do reps from full extension, to halfway up for x amount of sets. Then do sets from Halfway up, until peak contraction.
Finish off, with full reps. Try and keep reps up to 6-12 for full reps. If you can do more, add weight.
Another tip.
Dont just go up, and down, mindlessly. Say youre doing full reps.
Slightly lean back, and pull your Lower Chest, towards the bar. Stop DEAD-at the top, contract your back muscles, by using your brain, and mind/muscle connection. then try to pinch your scapula together,,,,, SLOWLY, Lower yourself. Stop Dead, pull as hard as possible, to the top of the movement, Stop Dead. Contract Back Muscles. Slowly Lower- Repeat.
Start from a dead hang, Pull as hard as possible, throughout the movement, to the top.
But, all exercises should have a Start, and dead stop portion, to make sure 1000% no momentum, is used. Now, after one cannot move a weight, on certain exercises, if no training partner, one can cheat a bit, to grind out 1-3 more reps, you couldnt do, without, cheating. But, only cheat just enough, to make the complete rep. Curls, are a good example. Dumbbell laterals.
A Bench tip. From Franco Colombu.
Always warm up, with light DUMBELLS.
The reasoning for this is?? The Bicipital Tendon, runs from the Shoulder/front delt, through what is called the Bicipital Groove, down to the elbow joint. This Tendon, is often Not Seated, in the Bicipital Groove, and when one does Barbell Bench. It Potentially Compromises the tendon, and over time, can cause Tendonitis, arthritis, tendon rupture, and other injuries.
Dumbbell warmup, allows the tendon, to become seated, in the groove, as dumbbells provide a much wider range of motion, and is conductive, to seating the tendon properly. 2-3 light warmup sets. 15-20 reps.