Use with 11/32" Aftermarket Aluminum heads.

Universal Dual Spring Kit, 140 Lbs Seat, .650" Lift, Hyd Roller, 10 Degree Hardware

Spring base size requirements: 1.480" OD or bigger w/ a guide flange diameter between .558"-.562"

This dual spring kit is for use with aftermarket aluminum heads running a high lift HP Hyd Roller cam.

Most aftermarket heads have a guide collar/flange diameter of .558" to .562" Measure the guide flange/collar right where the guide contacts the spring base. (not above where the seal fits)

Works with a wide range of high performance cam profiles and is suitable for select applications running boost. To verify compatibility, send your cam details to us for review. If turbo-ed or supercharged, please provide boost figures.

       Included Items:

• 16- Dual Coil Valve Springs, VS-99893
  
• 16- Chrome Moly Steel Retainers, 10 Degree, # R-378
  
• 16- 11/32" X 10 Degree Machined and Hardened Steel Locks (32 Pcs)
• 16- Chromoly Steel Locators, 1.475" OD, .795" Step, .568" Center Bore
  
• Installed Height Spec Card

      Spring Specifications:

• 1.460" Outside Diameter
  
• .805" Inside Diameter
• Seat Pressure: 140 Lbs @ 1.820" (valve closed)
  
• Spring Rate: 384#
  
• Average Coil Bind: 1.050"
  
• Accepts Up to .650" Lift

     Open Pressures:

• 332 Lbs @ .500" Lift
• 353 Lbs @ .550" Lift
  
• 374 Lbs @ .600" Lift
  
• 397 Lbs @ .650" Lift
  

To verify fitment on your heads, check the following specifications. (must be measured, most head manufacturers do not supply all these specifications)

1. Measure the guide boss diameter down next to the spring base. It should be between .558"-.565" here.

2. Measure the OD of the spring base, it will need to be 1.480" or bigger.

3. Measure the valve tip length. This is the distance between the topside of the keeper/lock groove to the tip of the valve. Most valves will have a .250" tip length which is what is required here.

4. Measure the valve stem protrusion. This the distance between, the bare spring base to the tip of the valve. (No shims, cups or locators for this measurement) Your heads will need 2.040" or more stem protrusion to obtain the required installed height. Anywhere between 2.030"-2.095" stem protrusion should work. For stem protrusions taller than 2.050", shims may become necessary. If your stem protrusion is more than 2.100", please reach out to us in advance of ordering.

5. Proper installation requires the use of an Installed Height Mic to measure installed heights. Be sure you have this tool and verify its accuracy. If you buy one of those low cost black installed height mics from amazon or ebay, it will need to be re-calibrated as those are never accurate from the factory. If your mic is off, it can be sent to us for calibration. We offer several service options for installed height mics.

6 Processing Time: All AP spring kits are custom built to order- Please allow around 30 days for the kit to to be built and shipped.

Thank you, Alex~