Thank you Jerry, I have already check that and both options that I am looking at will work for my build, AFR suggest that anyone using the 195 or 210 on a 383 build use a 4.166 std head gasket. The heads that I am looking at are standard GM placement head. I am looking for advice on the the performance difference (if a noticeable difference) between old 210 heads and new 195 heads. Jerry thank you for pointing out thing I should (and have) look at before building a motor. I am really interested in your opinion on airflow/velocity difference between the 2 heads mentioned in my original post.