My 261 engine, which was not original to my 54 GMC obviously, had a 235 head installed on it when I bought the truck. Many people installed these higher compression heads on the 261's for performance reasons, but I also imagine they were replaced by the 235 heads simply because they were easier to come by than the 261 heads. I had my 235 head drilled for steam holes when I had my engine re-machined. Here is a picture of my head after being rebult and with the steam holes drilled:
http://community.webshots.com/scripts/ed...security=OWyhlH
