Modifications to stock converter (kinda long read)

For the least amount of parastic loss you need to remove weight and diameter and have a very strong lockup. If lockup slips that is loss.
Modifying a 12 inch stock converter over about 2200-2400 stall is called butchery. To do it requires removal of the back side of the stator which will cause a sluggish,sloppy,loose,inefficient converter. I would beware of anyone who claims it can be done properly. You must go to a smaller diameter converter to get more stall efficiently. The problem with that becomes a strong enough clutch system to hold with less diameter. There are only 3 options I ever suggest. The PI triple disc unit is the choice of many they have been around for several years and with the exception of the rattle noise that is inherent with the design and the cheap red lining clutch material. Most guys fry the clutches out and send the to circleD for a correct reline. CircleD builds good converters as well and BC-Automotive builds a great unit. Any of those will get the job done and you won't have to worry about it anymore. The edge and single plate PI units are junk. The clutch in them is weaker than your stock converter clutch. Another bad thing about the 12 inch converter is that they are very prone to ballooning.
Alan
 
Whatever torque converter you get, I would be sure to get something that has a high carbon friction lining for the clutch unit. Anything else like Kevlar or raybestos will deteriorate very quickly under full throttle lock-ups.