Well, let's see if I'm the world's number two authority, after Philippe, on Monogram's slot car kit production in the sixties...Nothing wrong with Monogram, but are you able to figure out all the different versions of their kits within the four years of production by now?
First Generation Kits
1/32 Scale
MGA Sports Car
'32 Deuce Roadster
Porsche 904 GTS
Cooper-Ford
Ferrari GTO/LM
Lola GT
Ferrari 275P
The MGA and the Deuce Roadster were issued as part of Monogram's first series in 1964. This was then supplemented with the release of the other kits in late 1964 and throughout the first part of 1965. These kits all came with an X-100 motor.
1/24 scale
'34 Ford Coupe
'36 Ford Coupe
'55 Chevy Hardtop
'58 T-Bird
'40 Ford Pickup
Duesenberg
Mercedes 540
The above kits were also issued as part of Monogram's first series in 1964. Although the motor and chassis parts of these kits came sealed in a tray, the plastic body parts were loose (at least initially). These 1/24 scale kits also came equipped with the X-100 motor initially but the X-100 was replaced by the bigger and more powerful X-200 motor after a number of months. A sticker on the box was used to herald the change.
Ferrari 275P
Scarab
Porsche 904
The Ferrari 275P was then released in late 1964 and the Scarab and the Porsche 904 in 1965. These later 1/24 scale releases came equipped with the X-200 motor and with their component parts all sealed in a tray.
The first generation kits were packaged in full art boxes. Here's an example of a first generation kit:
Second Generation Kits
1/32 Scale
Porsche 904 GTS
Cooper-Ford
Ferrari GTO/LM
Lola GT
Ferrari 275P
Ford GT
Ferrari 330P/LM
Lola T70
Lotus 33 Grand Prix
Ferrari Grand Prix
The 1/32 scale second generation kits came with swing pick-up arms and racing slicks replaced the regular rear tires with which the first generation cars were equipped. The two Grand Prix cars were issued with an X-88 motor while the rest of the cars were issued with the upgraded X-110 motor.
1/24 Scale
Ferrari 275P
Scarab
Porsche 904
Chaparral II
Midget Racer
Lola T70 & Cobra Daytona Coupe (vacuum-formed bodies)
Ferrari 330/P2 & Ford GT (vacuum-formed bodies)
The 1/24 scale second generation kits were all equipped with swing pick-up arms, racing slicks, and X-220 motors.
The second generation kits were issued in white boxes throughout the latter part of 1965. Here's an example of a second generation kit:
To confuse the issue, Monogram continued to use the same model number for the second generation kits that had replaced their first generation counterparts. Any first generation kit that had not been replaced by a second generation counterpart continued to be produced as a first generation kit.
1/24 Scale Third Generation Kits
Ford GT Roadster
McLaren Elva
McLaren Elva (vacuum-formed body)
Chaparral 2D Coupe
Indy Lotus
Mustang & Chaparral (vacuum-formed bodies)
Ferrari 330P/LM & Ford GT Roadster (vacuum-formed bodies)
These third generation kits were all issued in 1966. The Indy Lotus came with an X-110 motor and the standard inline chassis. The other kits, however, all had a sidewinder chassis and the upgraded X-220S motor to be used with this chassis.
The third generation kits came in white boxes with the cars pictured within a coloured rectangle.
1/24 Scale RTR Cars
Lola T70
Ford GT
Ferrari 330LM
Vampire
Snake
Assassin
McLaren Elva
I'm sure there were also colour and other variants to these kits but I'll leave those and whatever corrections are necessary up to Philippe.