I usually get $400-600 for a complete LT1 with all accessories, wiring, and PCM. Price usually depends on mileage. I have never sold one with under 100k miles.
4l60e trans are $150-250, you might get a couple bucks more due to the low mileage.
These are all CL prices I have sold at.
1996 Impala SS - 45K original miles - 5.3 LS swap - Brand new Bilsteins...WHAT A DIFFERENCE!