All 700r4 trans have lockup torqueconverters They also have an orifice in the pump that cuts the flow to the trans cooler when in overdrive GM did this because the converter makes 95% of the heat in a trans but when its locked up it makes no heat GM wants the trans to run a about 280 degrees There a 2 basic 700 wire harnesses in the trans one for fuel injection and one for carbs. The one for carbs. has up to 4 switches in the trans and only one wire to the solonid if you have this type and you put 12 volts to the a terminal on the trans it will lock up in 4th gear only no kit needed If you have a efi unit 1987 and newer you need to drop the pan there is either one or two switches the wire harness needs to be rerouted so power goes through the 4th gear switch then to the solinoid and you need to ground the neg. side of the solinod to the trans this does the same as all those kits and costs nothing I've built 700 since 1982 good luck