Generally aftermarket concaves are built stronger. loewenmfg.com has stronger concaves and they are line bored, and they also have good selection of rasp bars.
PM, I put Trimpe bars in my 7720 T2 last year and I was very happy. My concave was ok. I would highly recommend the Trimpe bars. Call Ralph Trimpe 812-522-1398. He also has concaves. Good luck. Pullpin
