Technical Cadillac 390 Head Question

I have a pair of Cadillac 390 heads I just got to replace a pair that are dicey due to serious rust in the cylinders and the fact that the block had 5 freeze related fractures. On to the questions. I was under the impression that the left head casting number is 1468025 and the right is 1473449. The heads I just bought are both 1468025 and they are L & R. The other crusty pair both are both 1473449. What gives? Does the casting number depict the year only and L & R are just dependent on how it was machined from the raw casting? There are also some small odd looking plugs on the pair I just bought that are not on the crusty pair. The crusty pair came off a '60 motor and appeared to be original to the motor. What is the skinny on the numbers and the plugs?

JK

 

IDK Good question. https://www.jalopyjournal.com/forum/threads/caddy-engine-casting-numbers.397279/

 

Yup, that's a good question may be a good idea to ask here: http://www.modifiedcadillac.org/

 

The above article, (link), is one of the sources that made me ask the question as that thread says there are left and right casting numbers.

JK

 

Another thing I am curious about is the whole left and right thing to begin with. Is the only difference the machined water port or are there other left and right unique features? Studebaker machined the water port into both ends so that there are no left and rights. Remember, Studebaker was sued by GM, (unsuccessfully), for copying the Caddy. If a head could be machined to change its gender it might be worth looking into. Any thoughts? Keep in mind I am more of a Stude guy than a Caddy guy, .

JK

 

A couple of 'added' differences on heads is the obvious water temp sender on front of L/H and the rear of the head has threaded holes for firewall earth bonding straps ...

This kinda makes sense

 

OK, I feel the lists of casting numbers are for a given year range and written as XXXXXX / YYYYYY and not XXXXXX L / YYYYYY R, and the fact that they're also listed with the part numbers "made" from those castings as L & R, are what leads to the confusion. .

So, any thoughts on the little plugs on the 468025 castings?

JK

 

I have three 59 390's and all have the 1473449 castings both sides, I have a pair of 60 heads, same deal. The plugs are a mystery.... Obviously the part numbers for replacement heads do not correspond with casting numbers...

 

Wish we could still buy them for $78.82.

JK

 

Do your adapter SBC manifold to Cad work for 429 or just 390?