I am considering in replacing the Ignitor Coil that the former owner of my 72 240z had installed. I believe the coil is somelike weak. Anyone has installed Ignitor II Flamethrower coil? Any experience? I read it delivers 45,000 Volts.

 

This is the one i have currently installed in my vehicle:

 

http://www.thezstore.com/page/TZS/PROD/12-4020

I did install the Flamethower and electronic points in my '71 240Z.  My son also installed the same kit in his '73 240Z.

I am pleased, though I can't say "I saw X% performance boost".  It works, I think it's a good solution.  I've not measured the output!  

See my experience here: Electronic points – Installing PerTronix Ignition Kit

which one? Petronix I or II Ignition coil? Is there any difference between both?

I did install the Flamethower and electronic points in my '71 240Z.  My son also installed the same kit in his '73 240Z.

I am pleased, though I can't say "I saw X% performance boost".  It works, I think it's a good solution.  I've not measured the output!  

See my experience here: Electronic points – Installing PerTronix Ignition Kit

How do i verify if my coil is not weak???