If you've read any of my past posts, then you know that I ask a lot of "STUPID" questions. I'm always trying to learn as much as I can about the 351c, & in particular the one in my 72 Mach 1. There is tons of info. online, much of it is contradictory, so it's hard to know what's true. Even my own posts contradict each other at times. Again I'm just trying to learn. Recently I found the following web site...
The following quote was directly under the attached photo...
"Based on years of experience, I can tell you “4” means a 4-barrel head with large ports. The dome
indicates an open-chamber head. If there’s no dome (indicated by a dot), you’ve found closed-chamber heads."
I had not seen this before and I'm questioning the accuracy of said statement.
I look forward to any & all input.
The statement about the "4" is correct. If the head has the "4" it is indeed a 4V as opposed to 2V head.
The statement about the dot representing open or closed chambered heads is a new one to me. It will be interesting to see what our experts have to say.
Good question and I am curious to know the answer too...I do know Ford used 2 dots to identify early Hipo heads so there is some significance with the dot.
I don't want to try and say that I know for sure and yes the dot means that it is closed chamber, but mine are 4v closed chambered and mine have the dot on them aswell.
Again, the dot signifies that it is a 1971 head. The dot doesn't signify that the head is a closed chamber design(even though it is). 1970 4V Cleveland heads have a 4 with no dot, Boss 351 heads can be ID'd by their part # and screw-in studs. Boss 302 heads (Cleveland design), have no number cast into the top left corner, and can also be ID'd by their part # and screw-in studs. All the aforementioned heads are closed chamber, large port, large valve designs. I realize this may sound confusing., It's stuff learned from years of working with Clevelands. GXR
(06-25-2014, 12:07 AM)gxr02190 Wrote: Again, the dot signifies that it is a 1971 head. The dot doesn't signify that the head is a closed chamber design(even though it is). 1970 4V Cleveland heads have a 4 with no dot, Boss 351 heads can be ID'd by their part # and screw-in studs. Boss 302 heads (Cleveland design), have no number cast into the top left corner, and can also be ID'd by their part # and screw-in studs. All the aforementioned heads are closed chamber, large port, large valve designs. I realize this may sound confusing., It's stuff learned from years of working with Clevelands. GXR
Interesting... Do you know if Ford used the one dot 71 head on any subsequent year cars (i.e. 72, 73)? Kind of like a carry over.