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Valve Spring Kit, SB Chevy Vortec, Hi-Perf Hyd Flat Tappet, 110 Lbs Seat Pressure, VSK4H50

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New # VSK4h50, old # Vsk600vft
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Product Description

 Drop in fit, .550" Lift, SBC Iron Vortec

Valve Spring Kit for SB Chevy Vortec

Fits: High Performance Hydraulic Flat Tappet cams


Our Vortec kits are specially engineered for Iron Vortec &  96 iron LT1 Impala heads. That's right, no machine work required to set up a pair of these heads.

We engineered this kit with all the right parts just so Vortec head owners won't have to machine the spring seats or valve guides to run up to .550" lift.

Great for increased lifts including engines with 1.6, high ratio rockers w/ up to .550" lift at the valve.

Yes, works with stock or roller self aligning rockers as well as heads w/ screw in studs and guide plates and std, non self aligning rockers.

As you may know, Vortec heads have a problem w/ retainer to seal clearance. The stock retainers and springs do not allow for more then around .460" or so lift.

This kit is specially engineered to allow for up to .550" lift, all with parts which fit the heads without added machine work.

We use a special retainer and spring combination which solves two vortec head problems.


  1. The retainer to seal clearance issue.

  2. Spring base diameter issue (vortec heads will not accept std SBC springs)


The issue with clearance between the retainer and seal was solved by producing a special retainer which offers maximum clearance between the bottom side of retainer and the top of the seal. The bottom of the retainer is close to much "flush" with the bottom edge of the locks. This design offers maximum clearance without compromising strength or requiring the guides to be shortened.

Our springs are a perfect fit on the stock Vortec spring base.

Both problems solved!

Stock valves have .260" IN/.289" EX Tip lengths which will generally allow for up to .550" lift.

It it durable? Yes! This same kit is running on over one thousand Vortec engines world wide.


         Kit Includes:

  • Sixteen- High Output Drop In Fit Valve Springs
  • Sixteen- Chrome Moly Retainers, 7 degree
  • Sixteen- 7 Degree Hardened Valve Locks


For 110 Lb seat pressure, we recommend purchasing a hardened shim kit to facilitate setting up the proper installed height.

Due to the fact vortec heads were made in several countries, (US, Canada and Mexico) it would not be possible to offer a kit which could be installed without making sure the target installed height was correct.

To obtain optimum performance, installed height must be measured and shims added as required.

Recommended seat pressure for High Performance Hydraulic Flat Tappet cams is 110 Lbs.

Please note that each kit comes with a card which shows the target installed height figure.     


  • Outside Diameter- 1.270"
  • Inside Diameter- .880"
  • 110 Lbs @ 1.785" (See *Note at bottom of page)
  • 310 Lbs @ .550" lift
  • Coil Bind 1.145"
  • Beehive Spring? - No
  • High Performance Replacement Spring? -Yes
  • Part # Vsk4h50 for engines w/ vortec heads and flat tappet cams
     or mild hyd roller cams.

 Use with Hyd Flat Tappets cams up to 242 degrees duration @ .050" or mild hyd roller cams up to 218 @ .050"

Requirements- Valve Seal replacement is highly suggested. It's important for the installer to make 100% sure the seals are fully seated down on the guide. Seals which are not fully seated will reduce maximum lift capacity. We recommend measurements are taken between retainer bottom edge and the seal top to verify there is at least .030" clearance here.

OE GM Vortec heads normally use: 11/32" X .552" seals. Be aware some aftermarket heads (such as engine-quest) have different guide diameters. If you have aftermarket iron heads, it is advised to measure the guide before ordering seals.

* This kit is also works with some Hydraulic roller cams. Spring output is 30% higher then stock which will improve performance over stock vortec springs. A good choice for "smallish" Hyd Roller cams up to 220 degrees duration @ .050"

NOTE *- Each spring kit comes with with it's own installed height spec card. When setting up installed heights, use the specification listed on the card included with your kit.

NOTE-1- Spring installed height must be checked and shimmed as necessary.

NOTE-2- Not for Gen III LS series Vortec. Check our spring kits for late model Gen 3 applications

NOTE-3- We do not recommend the use of "HOWARDS" brand self aligning rockers. Due to their bulky design, clearance between rocker and retainer are either limited or non existent. Most other brands of self aligning rockers work fine. Be sure to verify suitable clearances exist.


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

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