67 327/300 HP Cylinder Head ID - Question

[Kirk M.]

I have a 1967 327/300 HP convertible. I had the valve cover off the driver's side today and took some pics. Car was built April 18th. Here is what I found:

Time Clock 1:00

GM
5

T

3890462
L275

From reading it seems to be the correct head (3890462) that was used in 1966 through May of 1967. I assume the "T" stands for Tonawanda. The date stamp confuses me a bit as one book states Tonawanda heads always used a two digit year date in the date codes. That would make it December 2nd, 1975 (?) or is it December 27th 1965, which frankly doesn't make sense either? Thanks.

Kirk

[Philip C.]

Re: 67 327/300 HP Cylinder Head ID - Question

I have a 1967 327/300 HP convertible. I had the valve cover off the driver's side today and took some pics. Car was built April 18th. Here is what I found:

Time Clock 1:00

GM
5

T

3890462
L275

From reading it seems to be the correct head (3890462) that was used in 1966 through May of 1967. I assume the "T" stands for Tonawanda. The date stamp confuses me a bit as one book states Tonawanda heads always used a two digit year date in the date codes. That would make it December 2nd, 1975 (?) or is it December 27th 1965, which frankly doesn't make sense either? Thanks.

Kirk

Hi Kirk nice photos would like to see one of the front of the head casting symbol, it seems you have a 66 passenger car head, Dec 27 1965 have seen many T heads and blocks with single year date, T as you said stands for Tonawanda plant. Take a look at the pass side head fornumbers and dates. Phil 8063

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

Will do. Why does it have to be a passenger car head, because the 3890462 wasn't used on vettes till late 1966 but it was used on other lines of cars prior to that? Thanks.

Kirk

[John H.]

Re: 67 327/300 HP Cylinder Head ID - Question

Will do. Why does it have to be a passenger car head, because the 3890462 wasn't used on vettes till late 1966 but it was used on other lines of cars prior to that? Thanks.

Kirk

That's correct - 462 heads were used on many passenger car applications in 1966, but not on Corvettes until 1967.

Are the casting symbols on the end of your heads machined smooth and flat, or are they rough "as-cast" surfaces?

[Joe L.]

Re: 67 327/300 HP Cylinder Head ID - Question

I have a 1967 327/300 HP convertible. I had the valve cover off the driver's side today and took some pics. Car was built April 18th. Here is what I found:

Time Clock 1:00

GM
5

T

3890462
L275

From reading it seems to be the correct head (3890462) that was used in 1966 through May of 1967. I assume the "T" stands for Tonawanda. The date stamp confuses me a bit as one book states Tonawanda heads always used a two digit year date in the date codes. That would make it December 2nd, 1975 (?) or is it December 27th 1965, which frankly doesn't make sense either? Thanks.

Kirk

Kirk------


Also, these are not original GM rocker arms. So, in addition to the heads likely being replaced, these rocker arms have been replaced, too.

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

Dang, it just keeps getting worse Up to this point the car has seemed pretty original, wonder what happened with the heads? Anyone got a used pair of early 1967 or late 1966 462 heads sitting around?

Kirk

[Harry S.]

Re: 67 327/300 HP Cylinder Head ID - Question

There must be some around. What are they worth? The set on my 63 are 3890462 and both are dated L 5 6. I need them till I rebuild my engine in 2011.

Cheers

[Joe L.]

Re: 67 327/300 HP Cylinder Head ID - Question

Dang, it just keeps getting worse Up to this point the car has seemed pretty original, wonder what happened with the heads? Anyone got a used pair of early 1967 or late 1966 462 heads sitting around?

Kirk

Kirk------


By the way, Tonawanda did not use 2 digit year casting dates on all castings. In fact, I believe that in earlier years, including 1965, a single digit for the year is most common on Tonawanda-cast pieces.

In this case, the heads are almost certainly Tonawanda-cast due to the "T" casting symbol and this may be further confirmed by the configuration of the ends of the heads if you post photos of that. Plus, I think this casting was long out-of-production by 1975. So, the date almost certainly has to be December, 1965. This would likely make these heads among the first of this casting number produced.

In addition to all the above, the date, alone, would almost certainly establish that this head is not original to the car. As far as how it got on the car, who knows? What is the casting information from the other head?

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

The car is "bubbled" right now, but I will unplug the pump and get all the information I can on the heads including the passenger side in the next couple of days. My car is one of those base 67's that has the May of 66 manifolds on it. Is it just out of the realm of possibilities that they also used some old, part number correct, heads cast in late 65 to finish her off?

Kirk

[Timothy B.]

Re: 67 327/300 HP Cylinder Head ID - Question

Kirk, It is out of the relm, your car should have flint cast 462's along with the engine block.

[David D.]

Re: 67 327/300 HP Cylinder Head ID - Question

Kirk, what is your serial number? Some strang things happens with the 66 and 67 small blocks. I have a late 66 original car wih engine components that are dated very near a very late original 67.

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

Kirk, what is your serial number? Some strang things happens with the 66 and 67 small blocks. I have a late 66 original car wih engine components that are dated very near a very late original 67.

16,469 and April 18th, 1967 birthday with engine assembled March 10, 1967.

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

The plot thickens. Seems that the passenger side is original.

Time Clock
6:30

GM
27

13 (not sure what this means)

3890462
C 9 7 (March 9th, 1967 - this would be one day before the engine assembly date of March 10th, 1967 - guess the heads were fresh off the press!)

Did not see an F for Flint. Is one suppose to be there?
Did see a "D" above the GM/27 (see pict)
Also found a "13" between two rocker arms (see pic)

So it seems that only my DS head was replaced and the passenger side seems original. At least the car is half correct!

More on the next post about the double humps on the front of the heads.

[Kirk M.]

Re: 67 327/300 HP Cylinder Head ID - Question

Here are some pics of the double humps on the front of the cylinder heads. Notice that the face of hump is rough on the DS (non-original, late 1965 head) versus smooth on the PS (original). PS is hard to see because of the AC on the car. Is that what you were asking about earlier John Z?

[Joe L.]

Re: 67 327/300 HP Cylinder Head ID - Question

The plot thickens. Seems that the passenger side is original.

Time Clock
6:30

GM
27

13 (not sure what this means)

3890462
C 9 7 (March 9th, 1967 - this would be one day before the engine assembly date of March 10th, 1967 - guess the heads were fresh off the press!)

Did not see an F for Flint. Is one suppose to be there?
Did see a "D" above the GM/27 (see pict)
Also found a "13" between two rocker arms (see pic)

So it seems that only my DS head was replaced and the passenger side seems original. At least the car is half correct!

More on the next post about the double humps on the front of the heads.

Kirk-------


There will be no "F" for Flint. The heads for Flint-manufactured engines were not cast at Flint. They were cast at Saginaw, MI, about 60 miles north. Occasionally, an "S" will be found as a Saginaw foundry casting mark but it's quite uncommon.

I do not know what the stamped "D" or cast "13" denote.