Where are you located? I'll be ouut there working in the garage this weekend, and I will try to dig down to it and get you some casting dates.
What is the exact build date on your trim tag?
I did have the tranny handy, and it is stamped P7R17, with the VIN stamped on it. It is a nice, unmolested trans, with the original part # tag and all the original bolts and keepers in place. I doubt if it has ever been apart, and the gear teeth and synchros lead me to believe the mileage on it is fairly low.
I'll try to get out there and post up some pictures. Based on that, if you are still interested we can see if we can get together on a fair price for everything.
I also have a 657 block that I had been planning to use for my 67. My car is a 12C build, and the other block is a casting K216 date. Block stamping is VII23YW. That one is standard bore, and the cylinder walls are rusty and the pistons are froze in the bores, but I think a machine shop would be able to get it apart and the bores would probably clean up at .030 or .040.
Thanks,
Tom