2001 Chevy Blazer Xtreme 4.3L V6, got the mach underdrive pulleys and need to know what size serpentine belt I need for it. Also! Can anyone give me a good tip on getting that screw out in the middle of the alternator, I almost stripped it trying to take it off! That thing would not come off, now I am not sure I should take it off, just replace the main pulley and get a slightly bigger belt, but what kind hmm, any advice?

 

To get that pulley off that alternator you are gonna need and AIR GUN. I almost guarantee it. If you can think of an easier way let me know.

 

Easier, buy a new Alternator

Less hassel, soak it with Liquid Wrench before even trying (but make sure you have some electical dip or sprayto clean out the LW when done).
More work, Impact Driver and a solid BFH
Fun way, Soak it in gas and light it up (burn babby burn), but then you wont have an Alternator any more (or truck if you forget to remove it first)

 

I will try that, but not the burnnig part, should have done that before I dumped over 2K into fixing it up. But there should be a specific belt to go on it, do you know which one off the bat? I live in Germany so my resources are limited...

 

what all underdrive pullys do you have and was it worth it or not really?

 

get the correct size torx and wrench and it will come right off. well at least mine did. ill get you the belt part number later

 

Underdrive pulleys add horsepower, but not very much. They also slow down the alternator to the point it doesn't charge or charge much at an idle, with a lot of your electrical circuits on (like headlights!) you'll be discharging at al idle. It also slows down the water pump. I know whereof I speak, I have them on my Corvette with digital gages, I can see what the charging volts are at all times. And I'm starting with a 120 amp alternator and I'm running a red top Optima battery. Running the underdrives MAY have gotten me a tenth, with a fully charged battery. They've been nothing but a pain in the ***.
PS: When I change to Vortec heads I'll go back to stock pulley's. OD pulley's slow down the water pump and alternator ALL the time, and save their most horsepower the higher the engine RPM. They won't do squat at the RPM you run your engine at 95% of the time.

PPS: Email the manufacturer of the pulley's at their website and they'll tell you the correct belt. How easy was that?.

 

belt number is a gates k060910. If you run the power and amp pulleys then your alternator will charge at factory specs.