It is an AC Delco AD244... tested one and got 225A~ at engine idle (700rpm) when cold then dropped down to a steady 120A~ at engine idle (700rpm) when warm. It tested MUCH better than my Iraggi 220A and a "no name" 300A we had on hand. GREAT alternators and you can get them on
ebay for under $100... IF it will work on your engine...
honestly though, for only 750 watts, I don't think you should have to do shit unless your alt is going bad or something...
EDIT: looks like the AD244 will work for you... some of the vehicles they came on, the bigger ones will generally have the 145A version, not the 130A. Personally the one I used was from a 2004 Suburban IIRC... got it on
ebay for like $65 shipped and that is the one Beusings Iowa Generator tested for me. Out of 4 alts, the only one that beat the AD244 is my 300A O.G. alt with a much smaller aftermarket pulley on it and it beat it by like 50A all around IIRC.
(2005-03) AM General Hummer 6.0L
(2005-04) Buick Rainier 5.3L
(2004-02) Cadillac Escalade 5.3L, 6.0L
(2005-99) Chevrolet, GMC Pickup, SUV, Van 4.3L, 4.8L, 5.3L, 6.0L, 6.5L, 6.6L, 8.1L
(2005-03) Isuzu Ascender 5.3L
(2005) Saab 9-7X 5.3L
If I was you I would grab an AD244 and get a smaller pulley on it as well, that can be done for probably $100~ and would most likely be superior to the HO alt. the shop is offering for 3z the price...