FAQ'S Answered By Art Carr (Tranny Guru)http://www.artcarr.com/resources/faq.acppWhich transmission is better, the 700R4 or the 2004R?Both transmissions, made for General Motors vehicles, have been adapted into a great variety of high performance applications. The 700R4 is a little better for heavier cars. It has a lower first and second than the 2004R. The 2004R is primarily for lighter cars and has a gear set that is higher in low and second. The 700R4 is a lower gear overdrive than the 2004R. In essence the 2004R is a closer ratio transmission than the 700R4.
What is the difference between a lock up and non-lock up transmission?Lock up transmissions use a special torque converter with a clutch applied by pressure supplied by the transmission. When the lock up occurs, the clutch in the torque converter is applied and the torque converter is zero slip. All torque converters slip to some degree. The slip is typically 5% to 10%. When we build a lock up transmission the torque converter is locked under certain conditions. Lockup transmissions can be very useful because you can reduce the engine RPM under lockup conditions.
When should I use a powerglide instead of a three speed?A powerglide is most useful in light cars with high horsepower to weight ratio. A powerglide as built by Art Carr Performance products allows the torque converter to multiply torque for a longer time. Torque is what accelerates the vehicle forward. Three speed transmissions with low rear end gears don't allow the maximum torque multiplication available from the torque converter. High horsepower (800 and up) to weight (2500 and down) ratios benefit from the powerglide.