[Healeys] Four electrical questions

[john spaur]

1. Does it matter if the black ground connections are attached to the 
shroud or the steel frame (rear lighting harness near the signal lamps)?
2. Does it matter which wire from the overdrive solenoid connects to 
the terminal on the gear box switch?
3. If so, which terminal does it connect too?
4. Is the BT7 tachometer mechanical? I would like to know if anything 
needs to be changed internally should I decide to switch to positive ground.

TIA

John Spaur
San Jose, CA
'62 BT7