For what its worth...
Napa replacement alternators (toyota replacement) NEVER work correctly on toyota vehicles. I see this every day at work. Do yourself a favor and go get a Remanufactured Alternator from your local Toyota Dealer...they're usually a little more than NAPA, but they work every time. Also, if you have an externally regulated alternator, then get a reman regulator from Toyota too.
If your goal is to simply eliminate charging problems, than I'd go that route. If your goal is to increase amperage, than the GM alternator coversion may be worthwhile. The direct fit high amp alternators are very spendy!
WT- I'd like to see some pics of your GM alternator setup...
Ryan
