• Mercruiser released eight sterndrive engines in 1972.boating on biscayne bay image by Wimbledon from Fotolia.com
  
  Mercury Marine introduced Mercruiser sterndrive engines in 1961. Mercruiser sterndrives combine the power and economy of an inboard engine with the maneuverability typical of outboard units. The first production propulsion system over 100 horesepower. In 1972, Mercury released Mercruiser engines ranging in size from 140 to 325 horsepower.
  
  

1972 Engines

• In 1972, Mercruiser produced three engines in 3.0, 4.0 and 5.1-liter displacements. Five larger sterndrives were available at 215, 270 and 325 horsepower. All eight sterndrives were four-stroke engines with gear ratios that ranged from 1.32 to 1.98:1.
  
  

Motor Specifications

• Motor specifications varied according to engine size. The 5.7 liter GM 350 ci was an eight-cylinder engine that produced 270 horsepower. With a 15-spline count driveshaft, the GM 350 had a minimum and maximum wide-open throttle rating of 3,800 to 4,200 rpm.
  
  

Propellers and Performance

• All 1972 Mercruiser sterndrives required A-style propellers. Five A-style propellers were available for the GM 350, ranging in size from 15-by-11-inches to 15-by-17-inches. Two left-rotation propellers could be installed for dual engine applications. Depending on propeller size, the GM 350 could operate at speeds of about 25 to 45 mph.