Under drive pulley?

**Edward-T** · 12-15-2011, 06:50 AM

In the market for an under drive pulley, any suggestions on brand and part number, and it takes the place of the harmonic balancer, correct?

**ls1camino** · 12-15-2011, 07:10 AM

ATI is on top of the market, but $500+ for a crank pulley is kind of steep for most people.

The most common dampener out there is the SLP/Powerbond 25% Underdrive Crank Pulley.

Don't forget that you'll need shorter belts for both your accesories and your A/C. Here are the part numbers:

Acessories: #K060763
A/C: #K040378

You'll also need a new crank pulley bolt, since the stock one is torque to yield and is non-reusable...I would suggest investing in an ARP Crank Bolt.

**Deviant LS1** · 12-15-2011, 07:45 AM

The SLP/Powerbond are only a couple pounds lighter than stock but do they have a larger lip for better belt retention.

I had an ASP 25% under drive pulley on my last car. Good fit, never threw a belt and it weighs almost half as much as the factory pulley.

**0rion** · 12-15-2011, 07:47 AM

another vote here for the powerbond pulley

**Edward-T** · 12-15-2011, 07:47 AM

thanks guys, is there a website that sells them? like Hawks, Summit, WS6 Store?

**0rion** · 12-15-2011, 07:49 AM

new era has them....site sponsor

Powerbond 25% Underdrive Crank Pulley for LS1 Fbody/04-06 GTO

**cpop98ws6** · 12-15-2011, 08:21 AM

I have an ASP on my car, no problems with it at all.

**Mr_Rich** · 12-15-2011, 08:34 AM

I bought an ASP pulley over ten years ago and never installed it on the LS1 that was in my car. This past summer I installed an LS6 in my car. The ASP pulley was installed on that engine along with an ARP crank bolt. I have ~6000 miles on my car since the install and it's working great. I've heard there may be charging problems when using AC when you have an underdrive pulley. I never reinstalled my AC system and it's not a problem for me. I always see over 13 volts on the gauge.