aug 64 -- casting #3782461. both heads front and back have the side of the "double humpies" machined off??? whats up with this anyone know?
Head can be from 62-67 327 194 intake 1.5 exhaust. By the years it could be vette. The marking?? I have no idea. might be a clearance issue on something.
Someone in the past did it to tell which was the front and back since there done on opposite ends. Why, just because.
Would there be a X after that number?? Seems there was two sets of heads with this same number. one with a X and another without. The X head was Hi comp (57.5cc), best ports of any OEM production cast-iron head, intake runner vol 170-180cc while the one without was Similar to 461X but with smaller intake ports. They say they were know to crack!!
My sneaky cousin used to modify double hump markings to make them appear as PP heads. He was very good at it. He always refused teardown at protests.
my circle track buddies do that to make them "non double hump heads" if they aint cheatin they aint breathen!
Looks like a machining error made while facing off the ends of the heads on the GM production line, nothing more.
over the last 40 years I have machined off the humps off over 50 heads so no one could easly tell what heads I had on my engines. Some short tracks made them illegal so you had to hide what you were running. I never sold any of my parts so it did not matter to me. Plus it took about 4 on. off the engine. the last part was to be funny.. later Bobby..
theres no X after the casting number. its a complete dates all jive. (heads block intake) 64 dated 327 from a 65 impala convertible. 250 HP. Powerglide.
It could be a tell tale mark done by a shop that re-manufactured (rebuilt) those heads... That's gotta be it!!
This guy nailed it. I have seen plenty of 461 castings machined like this. They aren't anything different or special from other 461 castings.
Just to dispell some myths that people hold about these heads..... All 461 heads cast before July of 1963 are X heads. Not all X heads had the X after the casting number. Some heads had the X cast into the bottom of water jacket on the underside of the cylinder head. ALL 461 X heads had a 62cc chamber. ALL 461X heads had 1.94 valves. Heads cast after July of 1963 were just standard 461 heads. They were not X heads.
Those tabs are heat tabs to tell if the head has been overheated. The machine shop that did the work on them is protecting their own intrest. The circle in the middle of the tab will turn color if heated, thus voiding the warranty.
chevrolet used many different cast marks and even they could'nt tell exactly what was what even though many guides exist that show what the marks are supposed to mean. peace
OK THANKS for all the info. this is the 4th complete 250/275 hp 327 i own 2 im running in cars. this ones headed out for a freshen up.
for some reason,most of the markings i've seen like that have been in marine applications. anyone seen the same?
It's difficult to see in the photos, but is that truly machined off, or could it be casting mold flaws? I've NEVER seen any that looked like that. Someone else was right, the tabs are overheat indicators for warranty purposes. Someone else wondered, "Canadian"; usually Canadian heads say Canada, cast in the valve/spring/rocker arm area. In the tech section, you will find a post about camel humps/double humps/fuelie heads, by FWilliams, but he used to have a different handle. Maybe he'll read this post and contribute. Butch/56sedandelivery.
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