Can someone tell me why some hipo heads had "4V" casted near the spark plug hole and other hipo heads didn't?
Did you look and can you share the casting dates?
5K2 date.
It is likely just a production variation. A survey could establish the transition date code. I'll start.
Casting Date "4V" present?
5K2 Yes
5K4 Yes
6B23 Yes
6B28 Yes
I have two HiPo 289 service heads dated 1973. I will check them as well and add to survey.
Cory
They used several patterns at a time when making up the molds - some may not have had the 4V on them. In addition to the part and date/shift codes you'll probably find some wayward digits that don't have any explanation except to the original casters who when they found some bad castings they could could be used to trace them back to the pattern.
Took a tour of the Cleveland casting plant when I was 14. My uncle was a Ford VP and ran the place. Decided on the spot Foundry work wasn't for me.
Pretty much the same way it was done in the 1960s.
https://youtu.be/DXwAnazjphQ?t=320
Same idea but 30 years of improvement in casting tech
https://www.youtube.com/watch?v=ziVhj2oifl0
Hi Cory, another one for your survey...
Casting Date "4V" present?
6A31 Yes
Found the service heads date 3M20 for December 20, 1973. I believe these are last produced HiPo 289 heads. These also have the "HP" cast inside, under valve cover.
I also found some earlier heads (4L16 and 5H20) on auction No. 267573597761
Plus two more service heads (8K20) on FB
Casting Date "4V" Present
3M20 No
4L16 No
5H20 Yes
8K20 No
I have a pair of June 1968 HiPo service heads, but they are on a car am I am unable to see if the "4V" is there or not. Maybe I'll try some mirrors.
Cory
I am curious if those 73 and 68 HIPO heads have the plugged thermactor ports ?
Some more:
"5L4" (pr.) yes "4V"
"3D18" & "3D24" no "4V"
And as to Bobs' inquiry, the latter 'do not' have casting provisions for the passage or the plug/bunghole machining. :)
Scott.
Quote from: Bob Gaines on May 13, 2026, 05:35:40 PMI am curious if those 73 and 68 HIPO heads have the plugged thermactor ports ?
Hi Bob, the 73 heads appeared to have a provision that are not drilled out as far as I can tell. There appears to be a fastener in position, but it looks cast in. I've attached an image. On the 68 heads these features are absent.
Cory
Very interesting . I had thought that after later 67 all of the service HIPO heads had the thermactor ports . Your 68 heads seem to disprove that theory.Thanks.
Starting to see a pattern. Still more data needed.
Cory's image lightened only to make it easier to see the "fastener in position" areas he circled - it really screws up the rest of the color of the shot but helps to se in the circled areas. - I can delete if he doesn't want it here.
Not the best picture, but if you zoom in on the lower left, you can see that my 68 hipo heads do not have the smog port either.
Roy
6M22 with thermactor ports
No 4V.
These may be service heads.
Is there a way to tell if they are?
Quote from: 6s1640 on May 13, 2026, 08:35:40 PMthe 73 heads appeared to have a provision that are not drilled out as far as I can tell.
The "provision", or recess, in the location of, if equipped, the thermactor plumbing is not "as cast", rather the recessed porting is of a "machining operation"; and if so, then if looking into the exhaust port isn't there a small casting boss presenting a bored thru-hole visible in that upper corner of the port? ???
Now you might have to look for details, as I see the heads have had some porting work done and it is often practiced to plug these passages; often with some rather creative processes.
Also, anybody know how late, chronologically, did Ford produce "service-replacement" castings for the 289 H.P.? :-\
Scott.
Cory here is what I can offer to the effort. Unfortunately many of my pictures don't have detailed pictures of all surfaces but this is what I could make out
Casting Date "4V" present? Additional Details
5K2 Yes 4V
5K4 Yes 4V
7F1 No 4V Has emission "bump" in the upper left of exhaust port face undrilled
7H23 No 4V Has emission "bump" in the upper left of exhaust port face undrilled
0M4 No 4V C8ZE Service replacements with emission port machined, drilled + threaded
3A6 (1973) No 4V C8ZE Service replacements with emission port machined, drilled + threaded
Couple more out in the garage I will check for 64-66's
Quote from: S412gofast on May 14, 2026, 07:18:24 AM6M22 with thermactor ports
No 4V.
These may be service heads.
Is there a way to tell if they are?
Hi S412Gofast, because the heads have a December 1966 casting date code, they could be either - Production for a 1967 GT350 or a service part. Because it has the 65 cast into as well, I'd guess more likely a production head for 1967. The service heads with C8ZE are definitely service parts.
Cory
Cory
Quote from: 6s1640 on May 14, 2026, 11:41:20 PMQuote from: S412gofast on May 14, 2026, 07:18:24 AM6M22 with thermactor ports
No 4V.
These may be service heads.
Is there a way to tell if they are?
Hi S412Gofast, because the heads have a December 1966 casting date code, they could be either - Production for a 1967 GT350 or a service part. Because it has the 65 cast into as well, I'd guess more likely a production head for 1967. The service heads with C8ZE are definitely service parts.
Cory
Cory
Cory
thanks for this info!
Carl
Quote from: 6s1640 on May 14, 2026, 11:41:20 PMQuote from: S412gofast on May 14, 2026, 07:18:24 AM6M22 with thermactor ports
No 4V.
These may be service heads.
Is there a way to tell if they are?
Hi S412Gofast, because the heads have a December 1966 casting date code, they could be either - Production for a 1967 GT350 or a service part. Because it has the 65 cast into as well, I'd guess more likely a production head for 1967. The service heads with C8ZE are definitely service parts.
Cory
Cory
I would add the head your discussing with thermactor ports would be a production head for a thermactor equipped 67 GT350. The non thermactor cars did not typically receive thermactor heads.
Quote from: Bob Gaines on May 15, 2026, 09:56:43 AMThe non thermactor cars did not typically receive thermactor heads.
Just to add to the above: And to the best of my experience, the castings were the same, this with the provision of additional cast iron material, but they just were not machined for the thermacter plumbing. :)
And this leads me to the inquiry of the cylinder head numbers I provided, this being of: "3D18" & "3D24" and with the fact that they as stated: "'do not' have casting provisions for the passage nor the plug/bunghole machining", my "first knee-jerk reaction" was that these were of 1973 casting production, but without the casting provisions for thermacter plumping, could these possibly be actually of 1963 production? If so, it seems they would prove to have been awfully early "289 H.P." stuff. :-\
Do we have any known examples of 1970's "service" head production without thermacter provisions of some degree, at least if only as cast? ???
Scott.
Pictures of the two heads I used for my engne build reveal the following:
Casting Date "4V" Present
5H23 (ID 20) Yes
5H26 (ID 19) Yes
Quote from: pbf777 on May 15, 2026, 01:15:06 PMQuote from: Bob Gaines on May 15, 2026, 09:56:43 AMThe non thermactor cars did not typically receive thermactor heads.
Just to add to the above: And to the best of my experience, the castings were the same, this with the provision of additional cast iron material, but they just were not machined for the thermacter plumbing. :) .........
That would follow the same pattern used for standard non-Thermactor 289 heads which had the addition material on the exhaust port just not drilled or machined for use on a Thermactor car
Quote from: pbf777 on May 15, 2026, 01:15:06 PMAnd this leads me to the inquiry of the cylinder head numbers I provided, this being of: "3D18" & "3D24" and with the fact that they as stated: "'do not' have casting provisions for the passage nor the plug/bunghole machining", my "first knee-jerk reaction" was that these were of 1973 casting production, but without the casting provisions for thermacter plumping, could these possibly be actually of 1963 production? If so, it seems they would prove to have been awfully early "289 H.P." stuff.
Scott.
HP289 pieces. The majority of 1963-64 model year engines had cylinder head assemblies that were based the C3OE-E and C3OE-F versions of cylinder head castings; machined as 1963-64 model year specification pieces. The C4OE-B head casting was introduced about April 1964 for 1964 engines near the end of the 1964 model year. C5OE-A head castings made it into "1964" HP289 engines the last few weeks of the 1964 engine model year for some of the last regular production five bolt bell housing HP289 engines made.
1963 HP289 engine number 1241 (near the end of 1963 engine production) was installed in a Fairlane. The engine was assembled May 20, 1963. Both cylinder head castings were C3OE-E casting models and their casting dates were 3D18 and 3D24.
By chance are the "3D18" and "3D24" dated castings you have the C3OE-E casting model?
Quote from: Dan Case on May 15, 2026, 03:42:39 PMBy chance are the "3D18" and "3D24" dated castings you have the C3OE-E casting model?
Well, I said to my self: "yeah, with that date code they'd have to be, right?" So now (thanks Dan! ::) ), I've gotta go drag 'em out to "verify" what they might actually be, versus what I thought I remembered them to be. But then that isn't such an easy task ya' know, as we put them on that shelf probably 35-40, or so, years ago, and an awful lot of other "stuff" has migrated, some somewhat precariously, on top of 'em at this point! :o
But anyway, to answer your question: No, they're "C5OE" castings. :)
And then, since I had to go digging and look just to be sure, I came a cross another set 8) (man, . . . . the "stuff" ya' find! ::) ), so for the survey add: "5D23" (pr.) No "4V"
Scott.
I spotted a set on the internet:
Castings: "C3OE"
Date Code: "3M23"
Casting Identifier: "289"
No "4V"
O.K., so now, not only do we have examples of "C3OE" & "C5OE" seemingly cast on the same days, we have a set of heads with the date code of "3M23", that are "C3OE" castings, but the one set of mine are "3D18" & "3D24" but they're "C5OE" castings? ???
Scott.