"0059122" is the partial VIN from the car that the block came out of.

YT is the block code that was used for 400's from '67-79, and again from '72-76. You still havent posted the number cast into the cylinder block back near the distributor. That would tell you what year of "YT" 400 that you have.

1094 is likely a casting date on the heads but the first digit would be a letter indicating the month. That first digit may be an "I" which would mean the casting date was September 09, 1974. Cylinder heads cast in September of 1974 woud have been used on a 1975 vehicle. Check for numbers cast into the top of the center exhaust ports on the cylinder heads. I'll bet you'll find "5C". Maybe that's the C you mentioned on the side of the "block" did you mean the head?

The "D" and the "N" woud have a pointer between them indicating whether the heads were cast on day shift or night shift.

The intake manifold was probably cast on September 6, 1974.