Custom Headers from existing Hustler Headers?

Are you planning on doing this yourself?

Yes, there is probably enough bends in those headers to make it work.

I would not expect a fabricator to want to do it this way, as they probably have access to loose mandrel bends, which would be easier to work with.

If you intend to do it, a fender well set of headers has a lot of tubing, and would be a great start, especially with the flanges and collectors.