Hello, it’s the ole ’56 KHK basket case neophyte again, trying to learn something about K model heads. I’ve known since the acquisition 5 years ago that I had multiple sets of heads in the basket, and that one set was good and one set was cracked so figured I was good to go. Well…….. knowledge is a dangerous thing and I now realize after cleaning them up and inspecting that the good set is for an early engine and the cracked set is for my engine (never knew prior to this that 2 different heads existed). So I ended up with nice set of heads I don’t need and a set of cracked heads I do need. Curious to know if people have been repairing such items. I know that almost anything can be repaired if the desire is there, but one of these heads looks like a real bear to take on as it is cracked all the way through in multiple places.
In reading this thread from the beginning I note it is full of useful information, but does not contain side by side comparison pictures of the early and late heads, so it is my intent to provide such content, since I’ve got the cleaned up heads right in front of me now. Also, some of the previous images in this thread were ebay related, thus no longer visible, so a more permanent image record is desirable.
Although I have a very limited knowledge of this subject, hopefully others with superior knowledge will jump in and help and in the end we’ll all end up being better informed. I think a good place to start the conversation is with the part #’s from the February 1956 K Model Spare Parts Manual that should contain the entirety of head information relevant to 1952-56 consumer K models (not the racing parts).
- K model cylinder head part numbers from 1956 Spares manual.jpg (13.5 KiB) Viewed 17707 times
The Spares Manual content and the earlier dialogue in this thread suggest that 2 basic head sets exist, the early heads for smaller valves and lower lift cams, and the later heads for larger valves and higher lift cams. The only thing I have to go by in this matter are the casting numbers on the heads in my possession, which are described below and are consistent with other’s earlier comments in this thread.
Early Front Head Casting Number16682-52, with numeral 1 underscore, label appears as negative on casting
Early Rear Head Casting Number16684-52, with numeral 1 underscore, label appears as negative on casting
Late Front Head Casting Number16682-52, with encircled E underscore, label appears as positive on casting
Late Rear Head Casting Number16684-52, with encircled E underscore, label appears as positive on casting
Below are pictures showing the 4 castings described above from various angles.
Combustion chambers of early K model heads
- low res early K model combustion chamber.jpg (106.2 KiB) Viewed 17707 times
Combustion chambers of late K model heads
- low res late K model combustion chamber.jpg (101.64 KiB) Viewed 17707 times