ASP Underdrive pulley for 3.4 DOHC

[SuperBuick]

So I bought this pulley from a known community member on facebook (not a scammer), and I installed it, and when I started the engine it instantly shredded the belt.  

 

I assumed I did something wrong but on closer inspection the pulley is way too "shallow".  Did I get a pulley for the wrong engine?  I compared the stock pulley on my 3.4 to my spare engines and they are all deep (like the black one in the picture).

The directions do not mention any spacer or anything.

 

 

[SuperBuick]

And grabbing some old photos from fast fwd performance on the internet archive, its hard to tell...

 

Pic 3 is for the pushrod motors...

 

 

[Schurkey]

Why sabotage the A/C, water pump, and alternator output?

[White93z34]

Does the 94-97 engine use a different harmonic balancer to account for the additional crank pulley? That could explain it. I assume you're installing on a 91-93 engine?

Also even all these years later I never knew ASP was a company let alone made parts for these cars.

[SuperBuick]

Not sure on the different balancer - thats a great point.  I only have 91-93 engines to compare to.

I'll try to get a look at a later engine to see if there is any difference.

 

Yeah ASP is a pretty common pulley company, or at least they were.  I definitely feel like I've known of them for a long time

[Bake82]

A 94+ 3.4 Harmonic balancer as per rock auto, which looks similar to your aftermarket pulley.  Rockauto does not list a 91-93 harmonic balancer.  Most likely explains the issue you're having