Bill Smith
Founder, 1929-2014
Speedy Bill
Since 1952
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America's Oldest Speed Shop ®


Speedway Manifold Filler Neck

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Has two 1/4" NPT ports and one 1/2" NPT port. 7/16" pipe nipple for overflow. Includes 3/8" mounting bolts, washers, and gaskets.
Speedway Manifold Filler Neck
Product Video
Speedway Manifold Filler Neck

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Watch the video below to learn more about Speedway Motors radiators.



Q & A

What's in the Box

This neck allows you to fill your cooling system at the intake manifold if you radiator is lower than the intake. It can be flipped over for RH or LH upper hoses, and has two 1/4" npt and one 1/2" npt hole in the back for bypass lines or sending units. Fill cap plate has a 7/16" pipe nipple welded into the overflow area.

Fits Small Block or Big Block Chevy V8.

You may also be interested in:

Moroso 63420 Manifold Filler Neck
(Part #54563420)

Makes manifold the highest filling point.  For cooling problems where radiator is mounted low. Fits both right or left applications. Sender mount. Fits GM V8, 90° V6.

  • Locates filler neck at highest point on cars with low-mount radiators to bleed off air
  • Unit can be flipped 180° for either right or left outlet location
  • Includes 1/2" NPT fitting for installing water temperature sending unit and two 1/4" NPT fittings for return lines on popular aftermarket cylinder heads
  • Made of 356-T6 cast aluminum; 3-1/4" high
  • Includes gaskets, bolts and washers, and standard size radiator cap filler neck
  • Cap is NOT included


Speedway 180 Degree High Flow Thermostat
(Part #91015703)

Speedway takes a quality Robertshaw 330-180 high flow 180° thermostat, then modifies it to function properly in high RPM, high flow applications. They feature a balanced sleeve design and are strongly recommended for any performance application. Fits most domestic applications.

  • 2-1/8" diameter 
  • High flow 180° thermostat
  • Balanced sleeve design
  • Recommended for any performance application
  • Fits most domestic applications

Learn more about the importance of the thermostat with cooling systems and how they work by reading our tech article, Cooling System Principles.

Safety Locking Radiator Cap - 28-32 Lbs.
(Part #91015728)

This safety lock cap for radiators is designed for high pressure, 28-32 lbs.  Provision to release pressure, taking the danger away from checking your race high pressure system.  High pressure cap raises boiling point of water.

Learn more about cooling systems, how to choose the proper pressure cap, and how they work by reading our tech article. Cooling System Principles

Hex Chrome Radiator Cap, 15 Lbs
(Part #91015606)

This unique hex style cap for radiators. Available in 15 lb. capacity. Brilliant chrome finish.

  • 2-3/8" O.D. of cap top
  • 2-1/4" I.D. of cap top
  • Will fit a standard radiator neck
  • Sealing surface (which sits inside the neck) is 1-1/2" O.D.
  • Cap sides are 7/16" tall

Learn more about cooling systems, how to choose the proper pressure cap, and how they work by reading our tech article. Cooling System Principles.