Looking really good Dave. I like the detail you've put into the alternator.
I had a similar idea with the coils. I originally had them in the foot boxes but I've found that I occasionally catch my foot on them when going for the clutch. I looked at mounting them on the block where you have yours but the way my headers run they wouldn't fit. It's also pretty tight around the starter motor.
In the end I made up some brackets to mount them to the chassis rails just behind the engine mount. Plenty of clearance around them.
I'm mocking up the plug leads at the moment. These are MSD leads with right angle plug boots from a Gen 1 Chev. Just got the get them re-terminated with the LS1 coil connections.
Keep the updates comming. We love the build threads.
Cheers