Plymouth cylinder head identification

[frijolito]

Can anybody help me identifying the cylinder head it’s supposed to be from a Plymouth. 
 

# 632955-3

other castings 

NH 

12-31

P

Edited September 7, 2020 by frijolito

[frijolito]

Edited September 7, 2020 by frijolito

[greg g]

23 inches long?  What is it going on?

[plymouthcranbrook]

This thread on The HAMB. Has some information regarding identifying  Mopar Flathead engine parts by casting number. Might be helpful:

 

https://www.jalopyjournal.com/forum/threads/help-identifying-mopar-flathead-6-in-my-1936-dodge.1058541/

Edited September 9, 2020 by plymouthcranbrook

[Eneto-55]

7 hours ago, plymouthcranbrook said:

This thread on The HAMB. Has some information regarding identifying  Mopar Flathead engine parts by casting number. Might be helpful:

 

https://www.jalopyjournal.com/forum/threads/help-identifying-mopar-flathead-6-in-my-1936-dodge.1058541/

Do you happen to have (or recognize) the book that scanned page came from?  (It appears to be only for Dodge - D2.  Wondering if there is a source for similar info for later model Plymouths, such as 46 up to around 55 or so.)

[plymouthcranbrook]

No. I just did a Google search and that is one of the results. I read it and thought it might be worth your time to investigate.  The thread mentions old Chrysler books that were used for that purpose.  Maybe you can go on the HAMB and contact the poster to see if he has any further information.  Good luck in your search

[Eneto-55]

I did later see that another poster in that HAMB thread mentioned the Hollander Interchange resource.  I did a bit of searching, and the one I could actually just look at w/o buying anything was for much later vehicles.  Another site listed books for sale, and it did include the year range of our vehicles here.

 

I have two L-Head heads, the one that is on my car, which is a 230 out of a 55 model, so it has the small hole for an electric temp gauge - one of the things I didn't realize until later, and something I haven't decided how to deal with yet.

  

The other one is out of a 49 1st series, and the only identifying marks on it are what I suppose to be a date code - 12-1. then, like the photo above posted by "Little Bean" a raised casting that has the letters NH run together so that the right leg of the 'N' is shared with the left leg of the 'H', and then the number 1120803-8.

 

The 230 head has no similar numbers or markings.  It just has a large D N with an arrow below it pointing to the 'D' (day shift?), a really large capital 'A', and the (date code) numbers below it read 12  10  54 (with interchangable plate fastening screws visible between each set of numbers).  Then it also has what appears to be a clock face, with an arrow pointing to the 1:00 position.  The large 'P' is in a different position altogether, toward the back of the head.  Also in that area it has the DPCD logo, followed by the number 1616823-4.

 

It is mostly just a curiosity, except that when my brother & I were sorting out the parts from our cars two years ago (that had both sat 'undisturbed' in our Dad's shop since the early 80's), he thought the extra head was from his 51 Plymouth parts car.  We both had parts stolen from the trunks of parts cars and from out-buildings over the years (especially heavy cast iron stuff, that made for a lot of weight for a scrap dealer), so it would be nice to know for sure if the second head I have here is mine, or his.

Edited September 9, 2020 by Eneto-55
correct spelling

[frijolito]

On 9/8/2020 at 4:29 PM, greg g said:

23 inches long?  What is it going on?

this is a 23'' head (23 1/2) going on a 1939 201 plymouth

 

Edited September 10, 2020 by frijolito

[greg g]

Should fit. Got pics of the combustion chamber side?

[frijolito]

On 9/10/2020 at 7:25 PM, greg g said:

Should fit. Got pics of the combustion chamber side?

 

[greg g]

Don't recall seeing a 46 and newer on with a stepped combustion chamber like that.  Should give a boost of compression ratio.