Looks ok to me but it's different than my F250; I had larger more pancaked booster. Try backing off the 4 bolts holding the booster to the mounting bracket and see if that brings the push rod in further. Something is causing that to be 1/4in further out.

If you decide to replace them both take yours with you to compare measurements right there on the counter. O'kragen took my old master cyl back under warranty 2yrs later; and credited me towards the new setup.

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I can almost guarantee it is the brake rod. I had the same trouble and getting it ti the right length fixed it. If the rid is too long, the master cylinder piston will not go back to release pressure back into the relief ports of the master. The fluid will just build up in the pad and shoe pistons until you gome to a grinding hault. Just get that rod to the right length (just clearing at rest) and you will be sailing away!