Alot of times when people took the motor and trans out of the car they never put the rods back in. They have to be taken off to remove the transmission. It doesn't really hurt to have it off. What it does is controls the neutral safety switch. You should be able to start you car in any gear. Also it controls the reverse lights. If you have noticed you probably don't have reverse lights. If you turn the collar on the steering coloum they will probably come on. In 68 the switch for that stuff in on the shifter. In 69 it's on the steering coloum. I don't know if they make the linkage aftermarket or not. I know that it's not alway easy to find the pieces that you are missing. There is a rod that goes to the transmission and that connects to a bellcrank assembly that goes into the subframe. The other rod connects to that bellcrank assembly also. It looks like your headers would probably be in the way, but I'm not sure about that. Hope this helps. Again check your reverse lights. You can still have them by rotating the coloum.