Use with 11/32" Aftermarket Aluminum & select aftermarket iron cylinder heads.

Universal V8 Dual Spring Kit, 173 Lbs Seat, .600" Lift

Spring base size requirements: 1.500" Min. OD w/ .558"-.562" guide flange diameter.

This dual spring kit is intended for use with aftermarket aluminum and iron cylinder head engines running a HP Hyd Roller cam in need of increased seat and open pressures.

Most aftermarket heads have a guide collar/flange diameter of .558" to .562"

On aftermarket heads, they'll need spring locators to hold the spring in place and to protect the spring base. This kit comes with chrome moly locators which fit over .558"-.562" guides. (guide measured at the spring base, not where the seals fits)

More and more builders are asking for dual spring kits with higher seat and open pressures, this is just one of several new kits we've engineered for these applications.

       Included Items:

• 16- Dual Valve Springs w/ Dampers
• 16- Chrome Moly Steel Retainers
• 16- 11/32" Machined Steel Locks (32 Pcs)
• 16- Chrome Moly Steel Locators, 1.480" OD, .699" Step, .568" Center Hole
• Installed Height Spec Card

      Spring Specifications:

• 1.470" Outside Diameter
  
• .705" Inside Diameter
• Seat Pressure: 173 Lbs @ 1.800" (valve closed)
  
• Spring Rate: 442#
• Average Coil Bind: 1.130"
• With 1.800" installed height @ .600" lift, there is a minimum of .050"/.060" before coil bind.

     Open Pressures:

• 394 Lbs @ .500" Lift
• 406 Lbs @ .525" Lift
  
• 417 Lbs @ .550" Lift
  
• 431 Lbs @ .575" Lift
  
• 442 Lbs @ .600" Lift
  

Purchase is for one V8 Spring kit for 16 valves. Springs, Retainers, Locators and Locks for 16 valves are included.

OK, customers who want to verify this kit will fit your aftermarket aluminum or iron heads can check the following dimensions.

1: To verify the spring locators will fit, measure the guide collar/flange diameter. This is the size of the guide right where it sits against the spring base. This should measure between .558" to .563" (do not measure where the seal fits on because this is usually smaller than the guides collar or flange diameter) Next you'll want to measure the outside diameter of the spring base. It should be 1.490" or larger.

2: To verify your heads will obtain the correct installed height, you'll need to take two measurements. The first one is to measure the tip length of the valve. Most aftermarket valves use a .250" tip length which is what you want here. This is the distance between the top edge of the keeper/lock groove to the tip of the valve.

3: The final measurement required is: Valve stem protrusion. The distance between the spring base to the valve tip. If there are any shims or parts sitting on the base, you'll want to remove them. This measurement is from the bare spring base to the tip of the valve. This length needs to be no less than 2.030" If it's a little more, that's ok because shims can be used to reduce the installed height. We carry hardened shims which fit under the locators as well as shims which sit on top of the locator.

Recap: With .250" tip length valves and a valve stem protrusion of 2.030", with locks included in the kit, the installed height will be close. When checking valve stem protrusion, be sure to check several intakes and exhausts on both heads to verify the measurements are close to one another.

The above information should make it easy to verify fitment.

We welcome your questions.

Alex's