Refer to the Identification page if you need to figure out what is laying at your feet.
CHRYSLER 331 GENERAL INFORMATION
The 331 engine was available in four (4) different configurations, with some overlap between each group. Also, the 331 was used in trucks, marine and industrial applications with some specific changes for each application.
The passenger car engine is divided into four (4) groups: 51-53; 54; 55; and 56.
Major differences are:
A change in the cylinder head from 53 to 54 (to larger ports and valves); and from 54 to 55 (a change in water pump design, and a revised coolant passage in the deck), and from 55 to 56 (a change to smaller locating dowels).
A change in the cylinder block from 53 to 54 (we get rid of the ‘extension’), from 54 to 55 (a change in water pump design, and changes in locations of a coolant passage in deck and core holes at the front of the block) and from 55 to 56 (a change in size of head locating dowel).
A change in front cover design ( including water pump style) from 54 to 55.
A change in intake manifold design from 53 to 54 and from 54 to 55. Note: the 54 -331 is the only year that the ‘early’ 331 was available with a 4-bbl intake. 51-54 manifolds house the thermostat.
A change in camshaft design from 55 to 56 includes changes in chain and sprockets and fuel pump eccentric.
There are three (3) distinct head gaskets: 51-54; 55; 56
Some ’53 cars have been found with ‘C54″ coded engines, some ’54 cars have been found with ‘NE55″ coded engines, and some very early ’55 cars have been found with ’54 style engines. Be sure of what you have before ordering parts.
The 55 Windsor engine [301 ci], has Spitfire (poly) heads, and similar shortblock to a 55-331.
The 56 Windsor engine [331 ci], has Spitfire (poly) heads, and similar shortblock to a 56-354.
The 57-58 Windsor and Saratoga engines are 354 ci, have Spitfire (poly) heads, and is similar to the shortblock of a 56-354.
All Windsor/Spitfire engines can be converted to a HEMI engine if you have: heads, rocker assemblies, valve covers, spark plug tubes, pushrods, and pistons.
ALL Hemi engines, 54 to 58, had 4-bbl intake manifolds.
Interchangeable 2-bbl manifolds are found on the ‘Windsor’ style poly-headed engine (55-58).
There is no correct 2-bbl intake for the ’54-331 just as there is no ‘correct’ 4-bbl intake for the 51-53 engine.
Camshafts interchange 51-55 (301-331); 56 to 58 (331 and 354). The 56 style cam can be used in the 51-55 engine with all appropriate 56 related drive parts.
392 cams are not interchangeable with 301-331-354 engines.
Crankshafts and con rods interchange; 301-331-354 except for the 51-53 crankshaft which is specific to the 51-53 block. The 51-53 crank has a flange projection that is 0.200″ shorter than other Hemi cranks.
Using the incorrect crank will create all kinds of trouble… Use the forging numbers to identify any crank in question.
Truck, Marine, and Industrial engines may have any of several design changes, or none, and be near identical to the passenger can style.
The trucks normally have special cylinder heads with sodium filled exhaust valve stems, valve rotators and water cooled intake manifolds. (The heads have a tall slender water port that must be modified for use with passenger car manifolds).
Many of the 331 truck blocks are 354 castings with the smaller bore.
Some truck engines have a thicker / taller rear main cap that requires a ‘long’ drive shaft.
Also refer to the Oiling section for information.