The Datsun 510 was produced from 1968-1973 as Nissan's compact sedan offering for worldwide consumption. But it was more than just another cheap economy car to rust in junk yards a few years later -- it was engineered to be an enthusiasts car, had European inspired sheet metal designed by Nissan's Teruo Uchino, and featured rugged overhead cam L-series power. Find this 1971 Datsun 510 Sedan with KA24E swap offered for $6,000 in Hayward, CA via craigslist.
This 510 isn't really a looker -- it has a flat (primer?) paint job and is missing various bits of trim...but under the skin it has a few surprises that might make you consider getting a 4-door 510.
Under the hood is a 2.4 liter KA24E inline-4 that was probably borrowed from an '89-90 240SX (or Nissan Truck/Pathfinder). Power for the SOHC 12-Valve version was listed as 140 horsepower and 152 ft-lbs of torque.
Power in this one is routed to a manual gearbox -- hopefully a 5-speed that would have come with the engine, but possibly the original 4-speed from the 510 sedan.
See another cheap 510 in the 510? firstname.lastname@example.org