I've been searching as to what I have here. my girlfriend bought a 2000 Monte Carlo SS 3 years ago and the guy replaced the engine with a supercharged one from 2003 Grand prix GTP, so he says. I was looking at how to put a serpentine belt back on once and notice all the L67 have 2 belts and L36 have 1 belt. what makes this so special? i was thinking maybe he added a supercharger to the original 3.8 NA and just kept the block? or whats so different about adding a supercharger and only needing 1 belt? ill post pics later but anyone know?

i know its not a Bonneville, but i have a Bonneville and thought this is best one to ask

I am not quite sure what you are asking, but every L67 I am aware of needs 2 belts. IN the case of series 2, it'* one for all accessories, and then one for the supercharger. If there is only one belt, than either it is a custom job that I have never seen, much less heard of, or there is a belt missing.

Even on a 'top swapped' engine, a second belt is still required for the supercharger.

Pics will definitely be needed if your setup varies from standard.

Even the Series 3 SC has 2 belts, never heard of either with a SC having one belt only.

I don't think he speculated a L67 ever had just one belt. He was used to seeing just 1 belt on the L36.

L67'* have 2 belts because the supercharger snout sticks out further than the other accessory drive pulley'*. Thus needing 2 belts and a 'double' harmonic balancer.

Ohhh, you are totally right Mike, I read that wrong.