Uuuugh!!! I did my research. I knew I couldn’t rebuild a 200-4R to hold 600hp myself. I spent ~5k very hard earned dollars to buy the best tranny I could get, using a CZ trans. Using one of the best builders in the country. Install went fine. I used the Bowtie Overdrives TV made EZ cable kit, using their spring as directed. Fired it up and idle line pressure was 115lbs. Shifts were way too high (>3100rpm off idle) and smashingly hard. This is classic long spring syndrome. I got 3 new TV springs, all of which were shorter (my builder’s “custom” spring, a stock CZ spring and another stock spring even a bit shorter) on advice of my builder and idle pressure dropped to 104 but this is still not drivable. Cable is absolutely adjusted properly. Car is not drivable. Shifts to 2nd at off idle at ~28 mph (way high rpm with 3.90 gears) and stack shifts after that with loud bangs. Anyone have advice? I’m afraid I’m gonna have to eat the cost of new tranny and go back to th400.