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Head Bolts or Studs: High quality head studs or head bolts with hardened washers must be used to prevent galling of the aluminum
bolt bosses. Edelbrock head bolt kit #8550 includes all bolts which must be used with these cylinder heads. Stock head bolts may be used if they
meet these specs for length: 1-3/4" (short bolts); 3" (medium bolts); 3 - 13/16" (long bolts). Bolts not meeting these specs do not have enough
thread engagement for use with hardened washers. The recommended hardened washers are GM #10051155, ARP #200-8511, or equivalent.
Rocker Arms and Valve Train: Stock (stamped type) rockers may require +.100" longer-than-stock pushrods (hardened preferred) to maintain
proper geometry. The valve springs supplied will accommodate valve lifts up to .600", which is much higher than stock rocker arms will allow.
Long slot stamped or roller rocker arms will be required if your camshaft has more than .480" lift.
CAUTION: GM LT-1 heads are factory-equipped with "self-aligning" rocker arms. These rocker arms have a stamped recess on the valve
tip end to guide the rocker arm on the valve stem which allows the rocker arm to guide the pushrod. Edelbrock Performer LT-1 PN 61909
cylinder heads are equipped with rocker studs and hardened washers for use with "self-aligning" rocker arms. Always check rocker-to-
valve tip alignment and adjust as needed. If using Non-self aligning rocker arms, Edelbrock recommends the use of PN 9660 guide plates
for use with 5/16" pushrods. If using guidplates the washer under the rocker stud must be removed and hardened pushrods MUST BE USED.
Valve Covers: Although Performer LT-1 heads will physically accept standard centerbolt valve covers, the emissions provisions are in different
locations. For this reason, valve covers specifically designed for LT-1/LT-4 applications are strongly recommended for use with OEM components.
Intake Manifold: Clean gasket surfaces. Do not use cork or rubber end seals. Use RTV silicone sealer instead. Apply a ¼" high bead across
each block end seal surface, overlapping the intake gasket at the four corners. This method will eliminate end seal slippage. Install gaskets and
intake manifold to factory specifications. Torque to recommended 35 ft-lbs. in the factory sequence. Refer to factory service manual.
Exhaust Headers: Any header or manifold designed for original equipment heads will fit Edelbrock Performer LT-1 Cylinder Heads. Exhaust
ports are CNC-profiled to match Fel-Pro #1404 exhaust gaskets, which are recommended for these applications.
Spark Plugs: Use 14mm x 3/4" reach gasketed spark plugs. Heat range may vary by application, but we recommend Champion RC-12YC (or
equivalent) for most street-driven applications. Use anti-seize on the plug threads to prevent galling in the cylinder head, and torque to 10 ft./
lbs. Do not overtighten sparkplugs!
INSTALLATION: Installation is the same as for original equipment cylinder heads. Consult service manual for specific procedures, if necessary. Be
sure that the surface of the block and the surface of the head are thoroughly cleaned to remove any oily film before installation. Use alcohol or lacquer
thinner on a lint-free rag to clean. Apply Teflon pipe sealant or suitable sealer to head bolt threads. Apply 30W oil or suitable lubricant under side
of bolt heads and washers. Torque to 65 ft./lbs. in three steps (40, 55, 65) following the factory tightening sequence (see Figure 1). A re-torque is
recommended after initial start-up and cool-down (allow 2-3 hours for adequate cooling).
SPECIFICATIONS
Head Bolt Torque: ...................... 65 ft./lbs. (in steps of 40, 55, 70)
Rocker Stud Torque: ...................................................... 45 ft./lbs.
Combustion Chamber Volume: .............................................. 54 cc
Deck Thickness: .................................................................... 5/8"
Valve Seats: ......... Hardened ductile iron, compatible with any fuel
Valve Size: ............................................ (PN 61909) Intake 1.940",
...............................................................................Exhaust 1.550"
Valve Spring Diameter: ....................................................... 1.450"
Valve Spring Installed Height:............................................. 1.800"
Valve Spring Seat Pressure: ...............................150 lbs. @ 1.800"
..........................................................................420 lbs. @ 1.200"
Max. Valve Lift: ..................................................................... .600"
Catalog #61905, 61919
Rev..11/09/12 - QT/mc
Edelbrock LLC • 2700 California St. • Torrance, CA 90503
Tech Line: 1-800-416-8628
Fig. 1 - Cylinder Head Tightening Sequence
®
Page 2 of 2
©2012 Edelbrock LLC
Brochure #63-0158
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