last fall, i just installed a 8 lb flywheel sprung 6 puck and clutch net 3x red pressure plate and a LSD.
The story:
I Was out with a friend doing some pulls. We take off from a light and the car went through 1st and 2nd fine, I pulled 3rd and still seemed fine. I got to the top of 3rd and it felt like the trans exploded(it pop-ed out of third). The trans would not go into any gear. I got the car stopped and still nothing it wouldn't go in to gear.i kill the motor and it would cycle through the gears fine except rev and 5th. i get the car home and pull the trans and open it up.
after 2 hours i couldn't find a dam thing wrong.

I started messing with the linkage and figured something must be bent. i pulled the linkage out of a spare installed it. I set the case on and it shifted fine.
i reinstalled the trans road tested it and all is good driving normally.
i went to do a 1st through 3rd pull. 1st was good 2nd was good and grind-grind 3rd.
the trans goes into 3rd easy at a lower rpm and normal shift.
when i try to shift into 3rd at high rpm and a fast shift or even a high rpm normal shift it will either grind or not go in at all.

all the gears and syncros look fine, there are no chips or excessive wear.

any suggestions?