Yes, interesting!
I think the first description of "inconsistency in manufacturing" leaves a mistaken thought in our minds. That sounds like the manufacturers can't hold to a specification. But the later discussion of 1980 - early '83 vs late '83 and on is more accurate.
The MPC shows:
16612 HOOD 80/86 F 150/350.U 150 E4TZ 16612-B
So there was a 1984 revision in the hood. There might even have been a previous 1983 revision that we don't know about. Interesting!
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI