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shovelhead harley replacement engine 93

The SH103 is the largest production engine that S&S and Flathead Power™ offer for shovels. This engine features forged pistons with a compression ratio of 9.7:1, a Super G carb, and dual plugged heads. Unlike the SH93 and SH93H, the SH103 engine will not fit in a stock frame without modifications because the overall height of the engine is .300 inches taller than stock. This engine is recommended for high performance applications. This engine is not for everyone!

Shovels 93 Engines

SH93 engines feature forged pistons with a moderate compression ratio of 8.5:1 and a Super E carb. The SH93 is a good choice for daily riders, and is great for touring applications.

Shovels 93H Engines

SH93H engines are an excellent choice to replace a tired shovelhead engine, and boost performance at the same time. Modern features such as late style hydraulic valve train, polished billet rocker covers, forged roller rocker arms, and a single fire electronic ignition, combined with larger displacement, add up to a powerful and dependable engine package.


  • 1966-’69 stock chassis electric start with alloy primary – flat side gear cover and flat timer cover
  • 1970-’99 stock chassis with alternator style primary
  • 1970-’99 alternator/generator and alternator custom versions custom bikes with 1970-’99 alternator style primary


Features and Benefits:

  • Natural crankcases and black powder coated cylinders
  • S&S hydraulic valve train and roller rocker arms
  • S&S Super Stock™ single fire ignition system
  • 1966-‘69 models have correct length sprocket shaft for stock primary and transmission
  • Alternator and alternator/generator models have correct sprocket length sprocket shaft for 1970-up primary and transmission
  • Alternator/generator engines include oil filter mounting bracket for generator location
  • Two-year warranty


  • 93", 93" high compression, and 103" displacements
  • Stock style generator, alternator/generator, or alternator crankcases


SH-Series Engine Specifications

Engine Name
Piston Type
Compression Ratio
SH93 93" 3 5/8" 4 1/2" Super E 585 S&S Forged 8.5:1
SH93H 93" 3 5/8" 4 1/2" Super E 600 S&S Forged 9.1:1
SH103 103" 3 5/8" 5" Super G 600 S&S Forged 9.7:1

Complete Carbureted SH-Series Engines

Billet Gearcover
Cast Gearcover
SH93 1966-'69 Chassis Generator - - 31-9906
1970-'84 Chassis Alternator 31-9905 31-9904
Custom Alternator/Generator 31-9979 31-9917
SH93H 1966-'69 Chassis Generator 31-9978 31-9909
1970-'84 Chassis Alternator 31-9908 31-9907
Custom Alternator/Generator 31-9980 31-9918
SH103 1970-'84 Chassis Alternator 31-9919 - -