Used set of Comp Cams hydraulic retro roller lifters, part number 853-16. One of the set has collapsed, and I have obtained a replacement but the replacement is marked "speed pro" for some reason (came from Comp Cams, I don't understand the discrepancy). You can have it all- the eight original pairs (only one of the 16 is bad) plus the extra pair to cover for the bad one. You know what these go for new, I'm taking it in the shorts for them but I don't anticipate building another SBC any time soon. We're moving and I could use the money towards our house down payment. I'm asking $250 shipped within the US. I do have these listed on Craigslist and some other forums, so please understand if they sell quickly. I'll send them to the first person with $$$, questions don't really count as a sale but I'm glad to answer any questions that you want to ask. I just don't want people upset if these sell when it's not clear if you are just kicking the tires.