I wanted to ask this in the electrical forum since this is kind of important to my question, and I hope the moderators understand I am not trying to post an ad. However, I am selling some wiring harnesses off of old Nova I got for free and am parting out. I realize these are expensive new so I feel like I'm asking decent prices for say, the engine harness and dash harness. My question is, I don't want to lead people astray, but don't want to rip myself off, so if I'm just selling harnesses, should that include the fuse block in the firewall? Thanks.

Last dash harness I sold was from a 66 Chevelle. I'm a nice guy so it went for $15.00. That's around what I pay for them if I pull one.
A used, non-cleaned and non-refurbished harness isn't that expensive. If one takes the time to clean everything, check out everything, and replace the worn items the price will go up.
Just an opinion.

If there are any on Ebay, you could get an idea of what people are willing to pay. I bought a complete dash from a '71, with the harness and fuse block for $10. Of course I have a '72 which does not interchange. So, prices can vary a lot.

dash harnesses include the fuse block in all the GM cars I am familar with. There is no way to separate them that I know. /so if you sell dash harnesses without the block, I would charge a lot less.