With an overdrive ratio of .70:1, the hydramatic 700R4 transmission is, on paper at least, a godsend for fuelthirsty musclecars. With 30 percent fewer rpm to turn, that's a lot of saved fuel and engine wear. Where hydramatic deviated from prior nonoverdrive designs was that the overall line pressure was governed by throttle valve (TV) position. If you've ever seen the little cable connected to the throttle and had to adjust it, you're already up to speed. Setting up a 700R4 for hot rod use means breaking out the line pressure gauge, tapping into the main circuit, and monitoring the gauge during a series of test drives. The TV cable adjustment is a tightrope act that balances having suffi cient line pressure for power transmission while setting the proper shift feel and rpm. If you've done it right without burning up your clutches and bands, pat yourself on the back-it's a diffi cult job rated "9" on a scale of 1 to 10. With that as background, TCI has just released its Constant Pressure Valve Body for 700R4, which takes the risk out of setting your TV cable adjustment. Now you can concentrate purely on setting the TV cable for shift rpm and firmness without being susceptible to clutch or band burnout. line pressure is now fixed, with no chance of ever encountering a low-line pressure condition.