Just picked up a nice set of ported 853 heads. They have been milled, the chambers are now 64.5cc. Anybody know what a bone stock set of 853's cc's at? Trying to figure out how much was taken off of the bottom of these so I can decide what gaskets/pushrods I will need. Thanks.

 

They should be around 66cc stock, but if the head has larger valves or looks like there was some grinding/blending done, you can't determine how much was milled based off the new chamber volume. For example, when I put 2.02"/1.60" valves in my 241 heads and blended in the top cut, I ended up with 68cc chambers.

 

thanks, these have 2.02 1.58 valves and it looks like the chambers have been touched slightly. your info helps.