I've just installed a new clutch and the fork has .525 inch free play. I've read it should have about a half inch but not over that and if it does I should shim the ball behind the fork. Is .525 too much and should I shim the ball?

.525" is pretty damn close to .500". However, the rule is if you cut the flywheel, you shim the pivot ball. Use a nice flat washer, like one of the ones on the diff cover studs. Thje Cap'n

If you put a one washer shim in there you won't be anywhere close to .5in anymore. One shim changes it quite a bit. I'd be very happy with the number you have now.

Just wondering how do you measure the free play?

I took the measurement with the transmission out of the car. You can do it in the car with the cable disconnected.
Push the fork forward as far as it goes. I use a plunge micrometer, place it on the fork where the cable connects, set the plunger about 1 inch out then zero the mic. I push the fork to the rear and measure the distance it travels.

Great Thanks gonna check mine this weekend before install