Yes, chain tension must have 3/4" to 1" slack. Place your driver in the car and put the wooden wedges underneath BOTH bird cages. Mark the wedges if you desire to make chain adjustments in the future without the driver. When you get the chain where you want it (3/4" to 1" slack), tighten the left side wing bolt until it touches the engine base. Then tighten the nut on the same wing bolt. I would put the driver in the car and remove the wooden wedges, if the chain is still where you want it, then get a white paint pen and mark the threads on the wing bolt right behind the nut. The next time you need to make a chain adjustment you can just crack the nut on the wing bolt then loosen the wing bolt by hand. To put the chain at the same tension just tighten the wing bolt by hand with the nut in its marked place on the threads. The chain tension will be correct, unless you have changed ride height, spring rates, driver's weight, clutch drum(clutch sprocket), axle sprocket (gear), and/or wheel base.
I have noticed that when the chain is too tight the bearings in the clutch drum seize up very quickly. When the chain is too loose the chain eats the teeth off of the clutch drum and the axle gear.
Here is what I have to REMEMBER:
EVER TIME I change the spring rates and/or ride heights.... CHECK THE CHAIN TENSION WITH THE DRIVER!!!!