YES, I BUILD POWERGLIDES, WITH PRO TREE BRAKES. I CAN TELL YOU THAT YOU BETTER KNOW A LITTLE ABOUT THEM BEFORE YOU START. I DON'T KNOW MUCH ABOUT THE C4 OR C6 BUT I HAVE DONE ONE REBUILD FOR ONE OF MY FREINDS AND IT WORKED GOOD BUT I DIDN'T PUT A BRAKE IN IT! I KNOW WITH A GLIDE YOU HAVE TO DRILL THE CASE IN TO PLACES IN THE BACK AND MODIFY THE PUMP ANS INSTALL A DUAL RING SERVO! AND THATS JUST THE START OF IT. YOU ALSO HAVE TO PUT MORE FICTION'S AND CLUTCHES IN THE REVERSE BECAUSE A BRAKE HOLDS THE TRANS IN 1st AND REVERSE AT THE SAME TIME THAT IS HOW IT WORKS AND IF YOU DO NOT MODIFY THE REVERSE AND ADD CLUTCHES TO THE HIGH CLUTCH DRUM THAT YOU WILL GET ABOUT ONE NIGHT OF USE OUT OF IT BEFORE IT BRAKES SOMETHING.