Sorry guys, just had to share my excitement. I picked up this 12 bolt about 4 years ago and always read the date code as K 21 8 and just assumed it was a 69 model year housing.. Today while doing final prep on a correct '67 12 bolt to go in my malibu, I thought they sure looked the same width there on the floor, so I put a tape across them and sure sh1t 53 1/4" backing plate to backing plate on both. I took a hard look at that casting date and it still looks like an 8 to me, but the part number (which I didn't bother looking at before) is 3894939 which is '67. Anyway, sorry for the pointless thread, but my enthusiasm is just lost on my girlfriend :) LOL!!!

Happy camper,
TJ