The 550 again followed the naming method of weight the vehicle would carry rather then the earlier engine size. The 550 was the replacement for the top of the range Lambro 200, which still came with the same 200cc engine from that model, but with a small power rise. Brakes were now hydraulic on all three wheels, to cope with the new power, although top speed still could not top 38mph.
The most noticeable difference between the 550 and the 200 was the use of twin headlights, a feature to be used on all future models. The Lambros were the first small carriers to use this important safety feature ahead of all its rivals.
Stamped metal wheel rims in line with the cars of the time were now used, along with an interior light for the cab. An alternator now replaced the dynameter to cope with the extra lights, Innocenti were now making use of the more normal motor industry items found on cars to improve their models further.
The rear compartment was enlarged further to previous models, now measuring 1420mm long and 1250mm wide, the boxed version measured 1015mm high giving 2.2 cubed meters of carrying space.
To launch the 550, Innocenti made extensive use of blow up elephants, as they had come up with a slogan of "Carry more than an elephant" for the new model. Every Innocenti dealer was issued with one of these inflatable elephants to display in their showroom windows. Thousands of smaller inflatables were also made, and handed out free of charge at town festivals to further put the product in the minds of the buying public.
The 550 also was known as the super in some markets, in fact over half the production ended up going abroad, with 17,000 units ending up in Turkey and Vietnam alone.