Formula for CC displacement

Doug Domm · 01-18-2009, 07:31 PM

I'm looking for a formula to measure CC displacement. I need to replace valve seats as some of my valves are sunk more than I would like them to be. These heads have seen a number of valve jobs over the years and I have no record of chamber volumes before and after each valve job. They are sbc 291 castings with 1.94 and 1.50 valves. My chambers are average 3 cc's larger than they should be. How many cc are gained for any given amount that I raise the valve. I realize that any formula used would only give a theoretical volume and I still need to measure but I would like some idea how much I can gain raising the valve. And yes I realize raising the valve should open up the runner volume as well but I do have lots of room there. Also on a chamber volume how much margin are most leaving for tech? Thanks for any help. Doug

01-18-2009, 07:31 PM	#1
Doug Domm Member Join Date: Apr 2006 Location: canada Posts: 251 Likes: 28 Liked 84 Times in 21 Posts	Formula for CC displacement I'm looking for a formula to measure CC displacement. I need to replace valve seats as some of my valves are sunk more than I would like them to be. These heads have seen a number of valve jobs over the years and I have no record of chamber volumes before and after each valve job. They are sbc 291 castings with 1.94 and 1.50 valves. My chambers are average 3 cc's larger than they should be. How many cc are gained for any given amount that I raise the valve. I realize that any formula used would only give a theoretical volume and I still need to measure but I would like some idea how much I can gain raising the valve. And yes I realize raising the valve should open up the runner volume as well but I do have lots of room there. Also on a chamber volume how much margin are most leaving for tech? Thanks for any help. Doug