New, one head cc'd 80 and the other was 83-4. At the recommendation of my machine shop (Boyd Machine Norman OK)they opened up the throat area just under the seat to just slightly smaller than the ID of the seat and then I blended it all in, aluminum is SO much easier to work than cast iron, I had them done in about 3-4 hours using a dremel and a flapper wheel and finished it off with a scotch brite wheel. They then sunk the valves with a 3 angle valve job to get the 85 cc I was after. They did check all the guides too. You could probably run them as is but by the time you pay for the heads ($900) and another $320 for the valve work its still cheaper than some others and they look really good on a stock appearing engine. In my case I also had to take a LOT of material out for pushrod clearance. I have adjustable rockers with a hyd cam.If I had known then what I know now I would have had the machine shop ream that too about .050. I also had to shim the rocker shafts .060 to make the pushrods work out. Not real sure why that was necessary since theoretically I only dropped the head .017 which is the difference between the .037 Fel Pro and the .020 Cometics but it works.