Can anyone help decode my engine please? I believe it to be a 230 ci or 250 ci. The number on the lower middle block are 2850817, GM 12 X is stamped on the lower middle of the block CON 2 at the back, H163 above the dipstick and F0829B is the serial # on the plate above the dipstick. The head casting is 4435F18 on the front passenger, 7880 in the middle and 8062 on the drivers side behind the manifold. Many thanks.