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SB Ford, GT40 .600" Lift Max Output II Drop in Valve Spring Kit, Hyd Roller, VSK7m48-M

  • Order for either .393"/.481" tip length valves or .393"/.393" tip length valves.
  • Vsk7m48-M Max Output, 130 Lb Seat, .600" Lift Drop in Spring Kit.
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Product Description


Drop In Valve Spring Kit, SB FORD GT40

Application: Hydraulic Roller, up to .600" Lift w/ 130 Lbs Seat Pressure.


Processing Time: Current processing time is around 30 days. This means your order will ship around 30 days after being placed.



  • This kit comes w/ parts to fit OE .393" & .481" tip length valves.
  • Kits can be customized for .393"/.393" tip length valves. Select this option when using our Gt40p-393 and Gt40p-393-A stainless steel exhaust valves.



We're expanding our Max Output series into three variations; Max Output I, II & III

This kit is from our Max Output II series.

It sports a custom made high output drop in spring with increased seat and open pressures as well as a full .600" lift range.

This kit fills a void in drop in springs, it offers dual spring pressures all in a drop in design- No need to machine the heads.

Perfect for cams calling for higher loads.

This Max Output II kit works with cams w/ up to .600" lift and up to around 250 degrees duration @ .050" (not to be confused with advertised duration which is always a higher number, use the duration @ .050" figure)

For those who love the cackle of a thumping cam, we've got you covered!



      Average Spring Specifications:

  • 1.487" Outside Diameter
  • Fits over stock SB Ford .995" Stepped Spring Base
  • 130 Lbs @ 1.765" Installed Height (see note * below)
  • 326 Lbs @ .500" Lift
  • 337 Lbs @ .525" Lift
  • 348 Lbs @ .550" Lift
  • 359 Lbs @ .575" Lift
  • 370 Lbs @ .600" Lift
  • Max Lift- .600"
  • Single Spring w/ Damper
  • Average Coil Bind @ 1.110"
  • Spring seat machining not needed to use this spring



     Kit includes:

  • Eight Intake Retainers and locks, labeled for easy identification
  • Eight Exhaust Retainers and locks, labeled for easy identification
  • 16 Drop in springs
  • Specification Sheet
  • Installed Height Specification




  • Vsk7m-48-M comes with parts to fit factory .393/.481" tip length valves.
  • To customize this kit for .393"/.393" tip length valves, use the appropriate check box at the top of the page. Select the .393"/.393" option when using our new Gt40p-393 or Gt40p-393-A stainless steel exhaust valves- Now available!


Recommendations- Measure valve spring height during installation and shim as required.

Note * Each kit comes with it's own target installed height specification card. For the best results, use the installed height specification included with your kit.





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