Installation Instructions for 51500 & 51505

Cylinder Heads for Small-Block Ford

**IMPORTANT - READ THIS FIRST**

These Heads are Intended for Racing Use Only!!

• Heads are cast using virgin 356-A alloy material and heat treated to a T6 temper

• Combustion chamber volume: 60cc• Intake runner volume 247cc as cast• Intake valve 2.100” 11/32” stem diameter, 5.350” length

• Exhaust valve 1.600” 11/32” stem diameter, 5.350” length

• Exhaust ports are in stock location and are machined to standard bolt patterns

• Spring pocket 1.690” diameter, machined to utilize spring locator 249-4785-16 for #51500 or 249-4772-16 for#51505• Premium AMCO 45 valve guides machined for .531” diameter seal

• Valve seats are cast alloy designed for unleaded gasoline

• Spark plugs: 14mm, 3/4” reach with 5/8” hex and washer seat. Always use anti-seize with aluminum heads.

• Custom guide plates for 3/8” pushrods are included. When installing guide plates take note that one pushrod slot is longer than the other. The longer slot is for the intake valve pushrod.

• These heads do not have exhaust crossover passage and will not work on any vehicle requiring EGR.

• Pushrods: Using proper length pushrods cannot be over emphasized!!!! Good valve train geometry starts when the right length pushrod is used for your specific engine combination: deck height, cam base circle, lifter length and choice of rocker arms. The fact is if you are using stock length pushrods your valve train is probably wrong. Before ordering pushrods use an adjustable pushrod checking tool to determine the proper length for your particular combination. Always use heat treated pushrods with guide plates.

• Rocker arms: Our stud location was established using standard aluminum extruded rocker arms and custom length valves. Always trial fit rockers before final assembly!

• Piston to valve clearance: Most performance applications will require machining of the valve relief‘s for proper piston to valve clearance or consider a set of custom pistons. This is a must check operation because the valve locations are modified and do not use stock dimensions.

• Head bolts or studs: We use stock dimension products.

• Intake manifolds: There are plenty of manifolds that do not match the flow requirements of this cylinder head. Itpays to have your manifold checked.

• Stud girdles: Stud location Custom. None Available.

• Intake gasket: Fel-Pro # 375-1262 or Mr.Gasket # 720-5832 or equivalent

• Exhaust Gasket: Fel-Pro # 375-1486 or Mr. Gasket # 720-5929 or equivalent

• Cylinder Head Gasket: Fel-Pro #375-1011-2 or Mr. Gasket # 720-5751 or equivalent

Any modification to the casting voids any warranty