There are few that pop up on Ebay, last 6.1 I saw on the E-Bag was a sleeved stocker went for $520...
paid 1k for a pair of 6.1s out of Philly 2 weeks ago on CL. there was a Bare block 6.1 on CL out of Long Island for $750.end of Sep guy sold it as I called.
as for pre 09 5.7s Car-part .com you can find them as low as $250 , 09-up about $450-500
if you want a 5.7 Up where you are in NY, I see $1500-2500 Junker rot bucket rams for sale all the time.