I was shopping for one a couple years ago, and that's inline with what I found. Even the local shops wanted that much.
I ended up here
http://jakesperformance.com/
Trans has been running strong. E-mails and phone calls were swapped so I could get the correct output shaft as it was in my K-20. (and to verify exactly what I was looking for.) edit- Looks like prices have changed.
I was going to tackle the tranny myself, but with winter approaching, I needed the truck.
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'86 C-30 dually, 454/tbh400
'73 K-20 350/350/205 (sold

)
I'm kinda like duct tape- no real purpose, but handy to have around.