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SB Ford, GT40P .600" Lift Max Output II Drop in Valve Spring Kit, Hyd Roller

  • Can order for .393"/.481" or .393"/.393" Tip Length Valves
  • Vsk7m49-M, 130 Lbs Seat, .600" Lift Drop in Spring Kit
Calculated at checkout

Product Description


Drop In Valve Spring Kit, SB FORD GT40P

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

Max Output II



  • This kit comes w/ parts to fit OEM .393" & .481" tip length valves.
  • Kits can be customized for .393"/.393" tip length valves. Select this option when using our Gt40P-393 or 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 engines calling for higher spring 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!




      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"
  • Average Coil Bind @ 1.110"
  • Spring seat machining not required


     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




  • GT40P heads normally have .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.

Please allow extra time for us to build your kit. Since these kits are all specially tested and assembled, additional time is required. Average shipping time is around 7 days after order date.





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

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