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Valve Spring Kit, SB Chevy VORTEC, Performance Hyd Roller, 120 Lbs Seat Pressure, Vsk4h52

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Product Description

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

Valve Spring Kit for SB Chevy Vortec, vsk4h52

Fits: High Performance Hydraulic Roller, 120 Lb Seat Pressure


Vsk4h52 fills the void in-between Vsk4h50 and Vsk4h53

In this series, we offer vortec kits w/ 110#, 120# and 130# seat pressures which covers a wide range of cam profiles.

This version works great for hyd roller cams with up to around 227 degrees duration @ .050"

A good choice for use with many of today's popular intermediate performance cams such as  GM's LT4 "Hot" cam profile as well as torque style EFI cams. Of course, for those running larger more aggressive profiles, we still carry Vsk4h53 which has 130 seat.

      Vortec valve spring kit list:

  • Vsk4h50- 110 Lbs seat pressure, hyd flat tappet cams 
  • Vsk4h52- 120 Lbs seat pressure, intermediate & torque style hyd roller cams <--- this listing
  • Vsk4h53- 130 Lbs seat pressure, bigger hyd roller cams


Alex's Vortec kits are specially engineered for use on Iron Vortec &  1994-96 iron LT1 Impala heads. They fit these heads without requiring a trip to the machine shop.

We engineered these kits specially for Vortec heads (& iron LT1)

You won't have to machine the spring seats or valve guides to run up to .550" lift.

Great for increased lifts including engines running 1.6, high ratio rockers.

Yes, works with stock rockers and with many aftermarket self aligning roller rockers.

As some folks know, Vortec heads have a problem w/ retainer to seal clearance. The stock retainers and springs do not allow for more then around .460"-.480" or so lift.

This kit is specially engineered to allow for up to .550" lift, all with parts which fit vortec heads without the need for 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 early damper type SBC springs)


The issue with clearance between the retainer and seal was solved by using 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 "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 this kit is engineered to work with. The use of aftermarket valves w/ .250" tips will most likely cause interference issues, be sure to only use w/ stock tip lengths.

Thousands of Alex's Parts vortec spring kits are in use all over the world.


     Kit Includes:

  • Sixteen- High Output Drop In Fit Valve Springs
  • Sixteen- Chrome Moly Retainers, 7 degree
  • Sixteen- 7 Degree Hardened Valve Lock pairs (32 Pcs)


To assure proper seat pressures are obtained, hardened shims are used to facilitate setting up each springs installed height. Installed heights must be measured and shims added as required.


Please note each kit comes with its own installed height specification card. Use the installed height spec included with your kit.     


  • Outside Diameter- 1.270"
  • Inside Diameter- .880"
  • 120 Lbs @ 1.770"
  • 310 Lbs @ .500" Lift
  • 331 Lbs @ .550" lift
  • Rate- 380#
  • Coil Bind 1.145
  • Beehive Spring? - No
  • Part # Vsk4h52 for engines w/ vortec heads and hyd roller cams up to 227 degrees duration @ .050"
  • For bigger Hyd Roller cams, use part numbers: Vsk4h53


Requirements- Valve Seal replacement is highly suggested. It's important for the installer to make sure their seals are fully seated down on the guide. Seals which are not fully seated will reduce retainer to seal clearance!


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.


NOTE 1- This is a custom built kit. Expect a 7 day wait period for the kit to be built and shipped. Expect possible longer delays during peak season.

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


Our Viton valve seals fit stock vortec guide boss diameters of .552"-.556" (OEM factory castings)


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

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