Originally Posted by Maine Sail
The series 6 and 7 share are very close in case size with the 7 being perhaps a tad smaller. The real difference is that the 6 series has a back up internal regulator built into it and is an isolated ground unit (nice feature) vs. case ground of the 7 series. The 6 is also available in larger output ranges.. I generally prefer the 6 series over the 7 series because I just feel you get a lot more for the money. With a simple switch you can just toggle to the internal regulator if the external goes kaput, and they can go kaput from time to time...
Wow. For some stupid reason, I'd assumed that the 6 series wasn't as heavy duty as the 7 series as the number was lower. Seems a little silly now. For $50 more, I can get the same kit from Binnacle.ca, but they have free shipping which just about makes it free to upgrade to the 6 series.
The 6 series is also an inch shorter (though a bit fatter). The bolt to bolt dimension is a bit more, so my tensioning issues will be a bit worse. I can live with that and buy or make a tensioning arm if need be.
This is all really coming together. I still think I'll go for the double pulley just because it's free and might be useful. In the meantime, I'll de-rate as much as I need to to keep the belt happy. Now all I need to do is size up some new battery cables and I think I'm good to go.
Thanks for the great advice (as usual)