Gathering parts for rotisserie rebuild of Bug Eye (floor replaced nicely and moving on). Regarding cylinder heads, "Tuning The A-Series Engine" 3rd edition, Chapter 9 Cylinder Heads, page 167, gives a good identification of heads. I have what is closest to Group D. 1 5/16" intake valve; 1 5/32" exhaust valve. Vizard (I understand he is THE authority) gives casting Number as 12G 940. Notes say "Good ports in standard condition." My casting number (under valve cover between cyl 2 and 3) is 12G 1316 - not 12G 940. My Intake and Exhaust valve size match Vizard dimensions. Head came off of a 1275, but of unknown history. As you read thru Vizard's description, and look at pictures, it is not the head on page 170 (sculpted by thermostat outlet); it looks like the head on page 169 - therefore not a turbocharged head.
Also Vizard gives a lot of detail about flow rate / capability with regard to intake and exhaust guide casting support area. Without measurements, mine appear to be better than the "bad" examples, but not as good as the "good" examples. This will not be a race engine, but I would like to get as much out of this head as economically practical.
Therefore, if head casting number 12G 1316 (as compared to 12G 940) is a good candidate for spending a little more money for significantly better performance, I'm in. If it is already a very good (later) casting and only needs standard valve job, I'll save money. If I have a lemon head, I'll look for another head. All informed advice greatly appreciated. Blueghost (particularly significant on Veterans Day).
Also Vizard gives a lot of detail about flow rate / capability with regard to intake and exhaust guide casting support area. Without measurements, mine appear to be better than the "bad" examples, but not as good as the "good" examples. This will not be a race engine, but I would like to get as much out of this head as economically practical.
Therefore, if head casting number 12G 1316 (as compared to 12G 940) is a good candidate for spending a little more money for significantly better performance, I'm in. If it is already a very good (later) casting and only needs standard valve job, I'll save money. If I have a lemon head, I'll look for another head. All informed advice greatly appreciated. Blueghost (particularly significant on Veterans Day).