GM Service Parts Operations
6200 Grand Pointe DR.
Grand Blanc, MI 48439
INSTALLATION INSTRUCTIONS
LT1 Aluminum Intake Manifold
For 1991 and Later Gen II Engines; non-EGR
PN 24502592 LT1 or PN 24502574 LT4
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DESCRIPTION:
This manifold offers a way to use a carburetor and standard distributor on LT1 style engines that are to
be used in non-emissions controlled applications only. It will only fit 1991 and later GEN II (RPO LT1) engines.
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EMISSION SYSTEMS:
This manifold will not accept any EGR (Exhaust Gas Recirculation) equipment or exhaust-heated
chokes. This manifold is not legal for use on any emissions controlled vehicle where such equipment is required.
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THROTTLE BRACKETS:
Due to the increased distance between the two left-rear manifold hold-down bolts (2.68” on
LT1 vs. 2.32” on standard Small Blocks) the throttle and kickdown bracket on some vehicles will not fit without
modification. A throttle bracket that mounts to the carburetor base bolts is recommended.
INSTALLATION INSTRUCTIONS
1)
Use either GM 12524653 intake gasket set (or 12367777 for LT4 applications) when installing this intake manifold.
2)
Fully clean the cylinder head intake flanges and the engine block end seal surfaces. Attach the intake gaskets to
the heads using the locator pins provided with the gaskets.
3)
Do not use cork or rubber end seals. They tend to slip and leak. Use RTV silicone sealer instead. Apply a ¼” high
bead across each block end seal surface, overlapping the intake gasket at the four corners.
4)
Set the manifold down onto the gaskets, taking care to not slide across the silicone. Using Figure 1 as a guide, first
torque all of the manifold bolts to 15 ft-lbs in the sequence shown; then repeat the sequence tightening to 25 ft-lbs.
5)
Most applications will convert to a standard distributor. If you are retaining your LT1 style front mount distributor
(you’ll need a special ignition computer to do this), a manifold distributor hole block-off plug is included. Attach it
using a standard distributor gasket, clamp, and hold-down bolt arrangement.
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If more information is needed about this engine, GM Service manuals are available from:
• Helm Incorporated • P.O. Box 07130 • Detroit, MI 48207
Rev. 2/15/01
