Where can I find ID information on GMC engines? I have a '48 228 Casting #6107326 with GMC-5 above it. There's also a serial number plate? attached to the block. It's hard to read but appears to be A 228 I or1? 94756. The head has 2136477 and AL underneath. Also on the head is Ferro 2 and F4 8. I assume this is a shift and date code?