Typically, the higher the stall, the more slippage overall. TYPICALLY I said, and is not the case in all converters. But there is ALWAYS a tradeoff. If its a street car, I wouldnt go much higher than needed because cruising around town below stall speed will generate a lot of transmission heat. A good efficient cooler is a MUST. A TA61 would be really happy with 3200 or so stall. I had a TE61 with 3000 and it was tolerable, but could have used more. Now I have a 3500 with a 63 and its awesome. Although I do have a lockup to reduce generated heat for simple cruising.
In my opinion, stick with lockup on a street car. Some will say non lock is the way to go, and they have realized no problems with it, but getting back to generating heat. Transmission life is severely shortened when run hot. Ask any trans guy.
Jim
