You mentioned that the engine runs good on one coil but not on the other. Did you check the wires on the bad distributor to make sure they are routed to the correct spark plugs? Steve Wong told me this is a common problem on 964's.

 

There was a problem with wires and caps, so everything is new now and works great. I'm still thinking about light weight flywheel ....

 

Did you solve the issue?

 

I am still curious why you ignored the first two replies who suggested that you try a system adaptation?

At least you have finally done it.