Swap head from 1949 to 1940 engine?

[Justinlb]

Are the heads the same on the 1940 and 1949 248 engines?

My 1940 buick needs some valve work soon and I cant bear to not drive it.

However my 1949 engine head is in immaculate shape and id like to use it if it fits. They look to be identical from the outside.

 

Thanks in advance😁