Hello, I have done a few of these.. It's been a while.. The Jake heads should be a 680 series.. There are spacers that go under the valve covers. The wiring comes off the aux relay in the dash and goes to the switch that you will install in the center dash panel, then to the clutch switch, and then to a micro switch on the injection pump at the throttle lever.. the late 70 models i drove, required me to hold the clutch pedal gently, or flip the dash switch off to stop engine braking while waiting at the red light. There are a lot smart people here, that can fill in the rest of the blanks..... The system is a combo, of simple electrical, and a hydraulic system that the engine provides through the jake heads.. youre rocker shafts have plugs located at the #2 and #5 oil galleries that come up through block. they will be removed and 2 little check valves will be installed there, to feed the jake heads. also, the jake reset screw lash is based on the turbo you have. Some were set to .060" and .080" based on the turbo and H.P. Text me: at 704-785-1738.. I have the engine books and will try to answer questions... Jojo.