I will be ordering a set here in a few when I order the stuff for the Blazer so I wanted to see what everyone is using here. I have used the ASP's (2 peice) on my 4.3 trucks before and had charging issues. I don't really care for all that, but every ounce of power will count in the end. I also need to know a p/n on the belt to use. Any advice is much appreciated.

 

I ordered the March pulley kit from TPiS, $118 includes the pulley kit and the belt.

http://www.tpis.com

 

The key to running an underdrive crank pulley is running an overdriven alt pulley with it. This takes care of the charging problems and the nice thing about the LT1 is no water pump drive pulley to worry about(no cooling issues).....Ed

 

There is not a lot of HP to be gained with the U/D pulleys, BECAUSE the water pump and AIR pump are not belt driven. Getting a U/D crank pulley, and then adding an O/D alternator pulley simply gives back a portion of that small amount of savings. Not worth it, IMHO.

 

I just ordered the asp one that is 23% underdriven at the crank and its 15% underdriven at the alternator (not overdriven). I also ordered a new 160 amp alternator from mralternator.com, I have no extra speakers or anything in my car except for a manual fan switch.....should I have any problems with with my electrical stuff or will that alternator be fine?

 

I have the 23% one-piece crank pulley from ASP with the stock alternator pulley. With normal driving, it's ok. But if you turn on the A/C, stereo, etc., it can dip close to the top of the red area.

With an underdrive alternator pulley too, I think you'd have some charging issues, even with stock speakers. The fans pull a lot of amps, as does the A/C.

 

our cars dont respond well to UD pulleys, even if they're "equalized" with an alternator pulley. spend the money elsewhere...

 

Thanks for the replies guys! I know the truck had a definate notice from the pullies, but these cars are a totally different story. I'll probably check into something else for right now.