Hey Keith,
Wow! As usual, I am impressed by your amazing handiwork of restoring your vintage cleaners. The conversion kit is an awesome bonus, too!
Since you have three of the original Electrolux USA uprights, Using the online patent information I found and Jimmy's knowledge, here is a list of all the model numbers and their characteristics. I challenge you to get one of each for your collection. The gray Silverado-Deluxe era one seems to be the most rare.
Model 1363 - yellow gold (3 brush roll options: soft, 3-row, and bristles/beater bars)—1977-79
Model 1363B "Heavy Duty" - tan - [upgraded air duct]—1979-80
Model 1363/Model 1363B "Heavy Duty" Commercial - yellow gold/tan - [branch office conversions: bag chamber label swapped out with one that bore 'Commercial', cord swapped out with longer 3-wire cord, brush roll swapped out with one containing 3 rows of bristles]—1978-80
Model 1451 "Automatic" - tan - [larger rear wheels; fifth screw added to handle grip; second point automatic airflow sensor shutoff added in clean air passageway between filter and fan]—1980
Model 1451E (enhanced) "Automatic" - tan - [quick clean-out port & rod added; indicator light moved to base]—1980-82
Model 1451E (enhanced) "Heavy Duty Automatic" - gray - [upgrades? - no patents found]—1982-84
Model 1451 E (enhanced) "Heavy Duty Automatic" - light sand gray - [upgrades? no patents found]—1984-86
Following are some online patents. Interestingly, Leonard E. Bowerman, the inventor of the first gen of Electrolux USA uprights was also a co-inventor of the second gen L-shaped ones with George Schick.
1. July 11, 1978 - Electrolux upright with magnetic clutch - patent summary (1363)
2. July 18, 1980 - Electrolux upright Automatic 2nd point shut-off summary (1451)
3. November 26, 1980 - Electrolux UR quick clean-out & rod summary (1451E)
4. Dec. 27, 1988 - Electrolux upright patent (Discovery II 1500)
