It just occurred to me that the pulleys I ordered for my swap are underdrive. I was wanting to keep the 130A alternator from my 3.8 but I have a 1200W amp and two 12s. Will the 130A alternator be enough or am I going to have to swap it out for something bigger?
You have to decide whats more important....3-5hp Or your electrical/ water pump operating correctly. Personally i look for HP elsewhere. At idle (like in traffic) a 130 amp doesnt even put out 100amps. Underdriving it will make it worse.
I have an 8inch that puts a load on my car at idle. I wouldn't play with underdrive pulleys unless I upgraded the alternator, which isn't worth it to me.
It's been too long since I ordered them to send them back is my problem. I was hoping that since I would be going carbed and removing A/C I be relieving some of the electrical strain.
You could just try it then. You should be able to run a system like that on a 65 amp alt. The issue is simply how much juice your alt puts out at idle RPM.
Give it a try, and see what happens. If the voltage drops too much at idle, then swap some pulleys. I run an overdrive pulley on the crank and the alternator. The water pump was spinning just a little too slow at idle to keep the car cool with an underdrive on it. I'd try them all first and see what happens. At most, I would guess you might have to put a smaller pulley back on the alternator to get the power back up. 130amps should be plenty to power the stereo system so long as the alternator is working correctly.