See also Installation of Top End for proper alignment of intake manifold.

HD Sportster Manifold Part Numbers
Year Model	Manifold Part#	Material	Throat Dia.	Bolt Hole Dims/Spacing	OEM Carb
1957-1971 Sportsters	27021-57	Cast iron	1.562“	.39” holes on a 2.688“ b.c. 1)	Linkert Tillotson
1972-1974 Sportsters	27021-71	Cast iron	1.562”	.33“ holes on 2.750” b.c. 2)	Bendix / Zenith
1975-1979 Sportsters	27021-71A	Aluminum	1.562“	.33” holes on a 2.750“ b.c. 3)	Bendix / Zenith Keihin “butterfly”
1980-1985 Sportster	27021-78 4)	Aluminum			Keihin “butterfly”
HD Big Twin Manifold Part Numbers
Year Model	Manifold Part#
1971-1975 FL/FLH/FX	27021-71 5)
1976-E1980 FL/FX	27021-71A 6) 7)
L1980-later FX	27021-788)

1972-1974 Sportster Intake Manifold (27021-71) 9)

1975-1979 Sportster Intake Manifold (27021-71A) 10)

Click Here to go to the TSB page in the Sportsterpedia and download TSB M-788 regarding the changes for the 27021-78 manifold.
In March, 1980, several modifications were made to heads/intake manifolds/clamps used on L1980 1200/1340cc FL/FX models to improve sealing capabilities.

1980-1985 Sportster Intake Manifold (27021-78) 11)

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These V-twin clamps (35-0419) work well for stopping intake leaks. The tool to install them is the same as any oiteker clamp pliers. ^{23)
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