The Amphicar was built in Berlin Germany. The years of production were 1961 to 1968. The production totaled 3,878 vehicles before it was shut down. Of these, 3,046 Amphicars were imported into the United States between 1961 and 1967.
The Amphicar was the only civilian amphibious passenger automobile ever to be mass produced.  It uses a rear mounted 4 cylinder British-built Triumph Herald motor producing 43hp.

The Amphicar's electric system was supplied by Lucas and is a 12 volt positive ground system.
Some of the components were made by other manufacturers such as Hella and Bosch.
The Amphicar has a top speed of 70 mph on land water and 7 mph on water. I've been told that was where the model 770 came from.  The land transmission was a 4 speed plus reverse and the water transmission was a 2 speed transmission that was only used in the Amphicar. It had one forward speed and one reverse. The water and land transmission could be run separately or together. This came in handy when launching or retrieving the car from the water.
The front wheels acted as rudders while the car was in the water. It was propelled by two nylon propellers.
The U.S. Government's EPA and DOT regulations that went into effect beginning with 1968 model year vehicles caused a major financial disaster for the Amphicar since the USA represented about 90% of all Amphicar market.
The plant closed in 1968.

We lived in Hoboken NJ from 1960-68, and the Amphicar importer was about 10 miles west in Moonachie - acres covered with Amphicars.  We had a 1959 Triumph TR10 (Standard, predecessor of the Herald) at the time, nearly the same engine.
The Amphicar importer decided to market the vehicle as an ideal way to beat the rush-hour traffic across the Hudson River from NJ to NYC.  They announced that they would show how the Amphicar could simply drive to the river, cross it as a boat, and drive up into Manhattan.  Lots of folks from the Press were at the ramp in Weehawken NJ when 2 guys from the importer drove down a boat ramp and sailed east.  The problem is, even on a calm day, the Hudson has about a 1' chop, and the water began to splash over the windowsills.  About 50 yards out, the driver made a u-turn, drove back out onto the boat ramp, and kept going. 
There was no further promotion of the Amphicar as a cross-Hudson commuter vehicle.

There are still some really nice ones around, we frequently have 2 or more at our Southwest Unique Little Car Meets, which rotate annually between Nevada, California, and Arizona (since 1981)

And Alan Jackson, the Country singer, owns one and drove into a lake to fish from it in the video of his song
"That'd be all right" a few years ago.