If anyone isn't familiar with this transmission it is built to handle 1000 crank HP. Its a fully automatic and has trans brake capabilities in D1-D3. I have not messed with transmission tuning yet. I just got the 408 running good. The first forward 1-2 shift is nice and soft. Every 1-2 shift after that is hard. Even with the lightest throttle applied. 2-3 is medium and 3-4 is medium under light throttle. Under heavy throttle they all hit hard just like a shift kit worked over transmission should. I wish the trans would 1-2 shift all the time like 2-3 does or 3-4 under light throttle. It does great on the first shift of starting the car. After that it hit hard. My line pressure under throttle is 190-200. The converter locks up like it should and overall I am happy with everything. How can we make light throttle shifting 1-2 softer, but retain the firm shift under heavy throttle? Why does it shift good then shift hard after the first shift? I am reading line pressure from a hose and gauge coming off the transmission. It also seems to shift softer when its cold. After the fluid warms up it shifts harder.