Springs Fit Factory Heads, No Spring Seat Machining Required.

MAX OUTPUT II, Drop in Valve Spring Kit, for Single Groove Valves

Application: 351C, BB FORD up to .620" lift w/ Hyd Flat Tappet Cams

This drop in spring kit was developed for use with Ford OE "stepped" spring base heads.

The springs fit factory heads without the need to machine the spring base or remove the heads to bring to the machine shop. Drop in springs can be installed right on the car if required.

These are from our Max Output II series. Max Output spring kits offer increased open pressures to meet the needs of more aggressive large size cams.

Max Output II kits are for bigger cams w/ between 226-250 degrees duration @ .050" w/ up to .620" lift.

351 Cleveland w/ single groove valves or Big Block Ford 429/460 engines running moderate to very hot cams can benefit with Max Output II springs.

Need help verifying the suitability for your cam? Send your cam specs to us and include the cam brand and part number or a link to the specifications and we'll advise.

See Note 1 & 2 at bottom of page.  

     Spring Specifications:

• 1.487" Outside Diameter
  
• 110 Lbs @ 1.825 Valve Closed Installed Height
• 300 Lbs @ .500" Lift
  
• 322 Lbs @ .550" Lift
• 346 Lbs @ .600" Lift
• Max Lift- .620"
• Average Coil Bind @ 1.120"
  
• Spring seat machining not required

     Kit includes:

• Sixteen 7 Degree Chrome Moly Steel Retainers
  
• 32 Hardened 7 Degree Valve Locks
• 16 Drop in Max Output II Valve Springs
• Installed Height Diagram

     Fitment:

• 351 Cleveland w/ single groove valves
  
• Big Block Ford 429/460 engines.
  

 Please allow up to 30 days for us to build and ship your kit.

Requirements- Measure valve spring installed height and shim as needed. 

NOTE 1: Will not fit 351C engines w/ multi groove valves.

NOTE 2: When using high pressure springs, to help assure proper cam and lifter break-in, it's best to use lighter springs during the break-in process. High performance engine oil specified for flat tappet cam break-in is required. Do not use an oil additive with regular automotive oil, instead use high quality oil specified for flat tappet engine break in.

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