Q: which is best coil for 6cyl distributor ign system?

[PeepPaadam]

I am in the middle of making ignition system for my '67 911 hotrod. Since the car will have vintage look and feel, I will use distributor. It is a twin-plug engine, meaning 12 plugs for 6 cylinders and will have distributor made from Jaguar V12 Marelli and Porsche distributors. At first thought of using two 911 coils and original CDI boxes but the CDI boxes are a bit prone to failing and they cost ~200-300usd/pc used. Will drive the coils directly from VEMS with dual out.

Main issue is the short available dwell time, redline will be at ~7300 rpm (it is 911S engine). There are Bosch coils available with low primary impedance (0.6 ohms), that would mean low dwell time also, right?

[MWfire]

You have time for dwell around 2.2ms.
You need to measure the inductance of primary of coil to calculate dwell time.

But some cdi coils doesn't work good when are driven as inductive coils.

[PeepPaadam]

I would just buy some new inductive coils that would require low charge time. Problem is that I don't know which ones to buy

Didn't some BMW M30 etc coils have low charge time iirc, could anyone confirm?

[gunni]

I have had success with MSD Blaster coils in replacing the stock BMW coils on 6cyl engines.

Remember you can also half your charge time requirement by doubling coils like the old Jags of yester years.
so in effect using 4 coils.

Toyota has low charge time coils 1.8ms or so you can always use two of those.

The latest M30's allegedly had stronger coils. They are the non cylindrical ones.

[PeepPaadam]

Thanks for the tips!

Good thing is that since this is normally aspirated engine (though CR of 10.4:1), it probably won't have spark blowout issues but would rather do away of the troubles.

Did some research, apparently Bosch red "KW" coil has 0.9 ohm resistance and provides almost twice the voltage of the regular black one. Part number 0221119030.