I just bought a Spec' big hit comp lrg size. What a sweet bike. But because it was a large frame, it came with a 650 weight spring on the fox vanilla r shock. It feels like it is way too stiff. ! weigh between 170-185 lbs. (My weight swings quite rapidly) Is this shock too stiff for me?

NO, 650 if anything is too light. However I cannot say for sure as the spring weight depends on the design of the bike. Based on your wegiht i would say that a good spring weight for you would be around 850-950. However you should call specialized to confirm.

I don't know how much you know about suspension components, so if this is "DUH, I Know that", then please forgive this.

The preload may be set too high. Do you know you can unscrew the shock (spring) to lessen the pre-load?

If you look at the shock body, you'll notice one side is threaded. The retaining clip on that side of the spring is also threaded. You can grab a hold of the spring and turn it to loosen or tighten the pre-load.

L8R

No I know about the preload. In the instructions, it says that you should never turn the preload more than 2 times to get your sag, but what is your starting point? Right now I'm getting about 7~8% sag.