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Valve Spring Kit GT40, Low & Mid Lift Cams, Max Output Drop in, Up to .520" Lift

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Product Description

Fits Factory Heads, no machining required.

Drop in Spring kit for: Mid Lift Cams. (.440"-.520")

Application: SB Ford w/ GT40 Heads w/ 1.6 or 1.7 ratio rockers


We continue to develop specialized spring kits to suit various cam profiles.

This version of our popular GT40 valve spring kit is intended for mid lift cams. If your roller cam has between .440"-.520" lift at the valve, this is an excellent selection.

When used with a mid lift cam, this kit provides more open pressure than a high lift spring kit.

The .520" Max Output series is an excellent choice for Fords "lette"r cams as many other HP street cams including the TFS stage I profile.

If your cam and rocker ratio combo do not exceed 520" lift at the valve and has a duration @ .050" figure of no more than 230, this would be a good choice.

Low to mid lift cam profiles require stiffer springs needed to support high RPM.

High lift sping kits are designed to produce the correct open pressures at high lifts where this kit is designed to produce suitable open pressures at lower lifts.

This kit, part # VSK7E48-M is from our "Max Output" family.

As with our other GT40 kits, this one fits the stock valve tip lengths used in this application. (.393"/.481")

Fits GT40 heads without additional modifications; machine work is not required. Just set up the installed heights, assemble and go..


      Spring Specifications: (Average)

  • Spring Type- Heavy Duty Single w/ Damper
  • Machine work required?- NO
  • 1.480" Outside Diameter- fits factory castings
  • I.D.- Fits over stock 1.00" register step
  • 122 Lbs @ 1.785" Valve Closed Installed Height
  • 275 Lbs @ .440" Lift
  • 294 Lbs @ .480" Lift
  • 302 Lbs @ .500" Lift
  • 311 Lbs @ .520" Lift



     Kit includes:

  • Package of eight intake retainers & locks, labeled for easy identification
  • Package of eight exhaust retainers & locks, labeled for easy identification
  • 16 Drop in performance springs
  • Specification sheet
  • Installed height diagram w/ target installed height- Use installed height specifications included with your kit.



Requirements: As with any aftermarket performance spring kit, proper installation requires measuring the installed heights and adding shims as needed to obtain the target installed height as shown on the spec card included with your specific kit.

Buyers can order shims and or or seals by checking the boxes at the right of the pictures at the top of the page. These items are added in at slightly discounted prices with reduced shipping rates.

Note the Viton seals we now carry are absolute best SB Ford seals available on the planet. They have a ribbed ID which improves ease of installation and seals better around the guide ID. Don't use cheap gasket set seals for your street machine, get the best from Alex's Parts.


Alex's Parts- The smart choice in valve train parts~

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