Quote Originally Posted by vilefly View Post
Unfortunately, for the full 90 deg to be available, one would need a very fat rotor to get away it. but I have no definite intention of changing the spark advance much. So stock will still work for me. The 8 coils would allow one to reprogram a crazy-ass timing curve for sure.
I don't think you're understanding the maximum 90* of dwell number. This is a physical limit based on the basic engine layout of the LT1 and the fact that a single coil is being used in the ignition system. It has nothing to do with the timing advance being used. As long as the LT1 PCM is kept in control it also doesn't change even when switching to 8 coils.

On this engine, a cylinder fires every 90* of crank rotation. At most, a single coil ignition system can have the coil turned-on to magnetically charge it for the whole time between each ignition event. This will end up being a little less than 90* of crank rotation, but lets call it 90* just for simplicity.

At 6000 rpm, 90* of crank rotation is 2.5mS. That is the theoretical maximum possible dwell at 6000 rpm. Of course, some of that time will be lost firing the ignition and turning the coil back on so in practice the dwell time will be less. What this means is that the 3.2mS you measured can't be the minimum possible dwell of the LT1 ignition system. It is physically impossible to have that much dwell at any RPM above 4687 rpm and still fire every cylinder on it's compression stroke.

All the above assumes you turn the coil back on to begin charging it again right after it fires, not at the next TDC event where you see the next low-res signal. Turning it back on at the next TDC event or leading edge of the next low-res signal will significantly reduce the dwell time.