I'll bet the Y8/ZN photo is from early 73 production or pre-production, or whenever they started building the SD-455. Could this be one of the first SD-455s off the line? The engine is not completely dressed yet. Looks like the guy is wrestling with the unique SD distributor, so it's probably right after distributors were put in. Perhaps a staged shot since I assume the union wouldn't let management touch stuff unless it was pre-production, an emergency, and/or a staged publicity shot.
Note the lack of bar code stickers on the engine valve cover labels. I had always assumed bar-coded engine stickers started at the beginning of the 1973 production year, but obviously not. The manifest sheet you can make out
"455 Super Duty-Auto 1973"
The engine assembly number
12°
4 BBL L-S-2
"270" for the carb 7043270
"432" for the idle stop solenoid 1997432
"175-A" perhaps for the EGR valve 7040175
and a few of the other numbers.
Anyone spot a date?
Does "IAL" on the flywheel tage hide the word special?
