Mismatched Heads

[Northern Runner]

Found this a little interesting when I started disassemble of my 360 I recently picked up, cast in early January 1973 btw.
On the passenger side of the motor I found 915 head, on the driver side I found a 587 head.
Both have 1.88 x 1.60 valves and intake ports are the same dimensions. I know that 915's were used on 71-72 340's and 360's and they switched over to 587's on both motors in 1973.
The motor hasn't been ever apart until now and the cylinder bores still have crosshatch marks on them :headbang:
My general question is what's up with the mismatched heads? Just another example of weird things done at the factory?

 

[super-bee_ski]

Pontiac did stuff like that too

 

[mopar 3 B]

At least it appears to be the same head just a different casting.

 

[Roadbird]

Probably the last head before the switch and had to be used.

 

[Northern Runner]

I figured other brands did this too...but I had never heard or seen anything like this before! After I posted this I had the same thoughts Roadbird, this had to have been the last 915 on the line so they mixed em. It'll make a cool story though!

 

[dieseldazzle]

Probably cracked a head somewhere in its 40 year life.....