showme,
If I were you you, I'd look into using an alternator. As I remember, you're already using a 12V system and the Delco alternators are very reasonable and reliable. You can probably get one with an internal voltage regulator for less than $75.00.
Check this info out at
madelectrical.com . I have a 10 SI and it works great! Check your FLAPS, I'm sure they can get you set up.
Good luck,
