[67ChevyRedneck]

I've used that kit before. It uses the 4th gear pressure port on the outside of the transmission. It works very well for locking up the transmission, but the HUGE problem with the kit is that it does not unlock it when you apply the brakes (say, in a sudden stop.)

Some peckerhead pulled out in front of me a few years ago in Clemson and I had to hit the brakes hard. I missed the punk, but the hard stop from 50mph with the converter locked caused the truck to stall, with the power brakes dead it then took forever for the truck to come to a complete stop.

I now have a BTO kit with the brake switch. Very nice.