A recovery cap has a little flap valve right in the middle at the bottom of the cap were the water is.
You can pull it up with your finger nail.
A non recovery cap won't have this. The additional valve is the only difference between the two styles of cap.
Run the water level around 1 inch down...
You may already have a recovery cap. Plenty of info on the internet.
Recovery bottle and the correct cap and it will work. It is a good idea to fit this system.
It does take a bit of "effort" to get the switch in to this position.
The interior lights are ON permanently with the switch in this position - so you would not want it to be to easy and you may not notice the lights ON and flatten the battery.
I believe the first question you need to ask yourself is do I have the skills and perseverance to get this car going.
If not just go and by a nice one that you can just drive.
The tail lights usually go to ground through the tail light housings and the body shell.
When you were working on the coil did you disturb one of the ground cables under the hood?
These ground cables complete the circuit to the battery.
With the stall you have it is going to get up to the RPM were the larger header is no real issue - more of an advantage in the upper RPM range anyway most likely.
I found exhaust diameter was critical playing around with 750 CC motorbike engines.
The smaller the engine the more critical sizing...
As the engine heats and cools during operation the thermostat should open and close to keep the engine at the correct temperature.
Change the thermostat first job.