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*NEW* Max Output II Drop in style Beehive Valve Spring Kit for Ford 351 Cleveland w/ Hyd Flat Tappets

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Product Description

Beehive Spring Kit for 351 Cleveland

Max Output II Beehive Spring Kit, 351C Flat Tappets & Single Groove Valves

Fitment: Ford 351 Cleveland

Here is the long awaited Max Output II Beehive Spring kit for 351 Cleveland with Hyd Flat Tappets.

With their 1.72/1.73 ratio rockers, Cleveland engines produce a lot of lift, even with mild cam profiles.

We custom tailored this kit to work with hyd flat tappet cams in 351 Cleveland engines w/ single groove valves.

Good up to .650", these beehives fit right onto the stepped spring base Ford used on so many Cleveland engines.

This is a big deal because no other supplier has put the effort into creating beehive kits for Cleveland's.

Since this kit is designed to be used with single groove valves, they won't work with stock multi groove valves. At this time, we do not offer this kit for the multi groove valves in a flat tappet version but we do have one for hyd roller.

Proud to say, these are an Alex's Parts exclusive- made up to our specifications. We looked at the various beehive springs currently available from all the cam companies and none of them were suitable for this application so we went ahead and had PAC produce them for us.


  Check out the features:

  • Manufactured using Multi Arc Ovate Wire
  • Made in the USA
  • Seat Pressure: 110 Lbs for Hyd Flat Tappet Cams
  • Available Lift Range: .650"
  • Parts included: Small OD Beehive Retainers, Our Custom Beehive Springs and Hardened 7 Degree Locks
  • Fits 351 Cleveland w/ single groove valves (will not fit stock multi groove valves)
  • Spring seat machining is not necessary, the spring fits OE iron heads w/ a stepped spring base
  • If desired, they can be used with umbrella seals. They fit inside these springs without a problem.


       Add-On Options:

  • Premium Viton Umbrella Seals (Our premium viton valve seals are the finest available anywhere. Why settle for lower grade gasket company seals?)
  • Premium Positive Viton Valve Seals. (Guide Machining required; guides must be machined to .500")
  • Hardened Spring Shim Pack, Includes: 16 each of: .030" and .015" shims


        Average Load Specifications:

  • Seat Load: 110 Lbs @ 1.860" (Valve Closed) see note below*
  • Open Load @ .500" Lift- 296 Lbs
  • Open Load @ .525" Lift- 306 Lbs
  • Open Load @ .550" Lift- 317 Lbs
  • Open Load @ .575" Lift- 326 Lbs
  • Open Load @ .600" Lift- 336 Lbs
  • Open Load @ .625" Lift- 346 Lbs
  • Open Load @ .650" Lift- 357 Lbs


      Size and Other Specifications:

  • Small End ID- .651"
  • Small End OD- 1.095"
  • Large End ID- 1.000"
  • Large End OD- 1.450"
  • Solid Height- 1.086"
  • Spring Rate: 372#
  • .650" Lift Range (plus a .060" minimum safety margin before solid height)


Can be used with a wide range of hyd flat tappet cam profiles from Mild to Hot. If you want to verify compatibility, feel free to use the contact us link and forward the lift and duration @ .050" figures or simply send us the brand and part number so we'll look it up. Let us know how you plan to run the engine and if it has boost. (daily driver/cruiser, street/strip use, turbo, supercharger, spirited hot street tire burner, circle track, etc.)


For a limited time, we're offering this kit at a discounted price. Pick up a beehive spring kit, all for around the same price the other guys charge for 16 beehive springs alone!

Our customers know we're very serious about our spring kits. Our quality can be compared to parts selling for well over twice the price. When you order from us, you're getting the best possible value available anywhere.


 Average shipping delay is around 5-7 days after order date. If you need it quicker, be sure to order early or contact us about rush order costs.

*Note- The seat load installed height spec in this listing is for reference only, please use the installed height specification included with the actual spring kit.


        Questions & Answers:

  • Q- How important is it to measure valve spring installed heights?
  • A- Setting up installed heights is important for the following reasons:
  1. Measuring installed heights will assure the intended seat and open loads are achieved.
  2. Builders who want maximum performance will always measure their installed heights and add shims as needed to get the installed heights as close as possible to the target spec card included.


  • Q- How close do I need to get the installed heights to the target height spec?
  • A- As close as you can with a tolerance of minus .015" to target height. In order to improve installed height accuracy and if it's possible, it's wise to set it up between .005"-.008" on the low side of the target height. Once the engine is run, the locks will seat further into the retainer. This is a natural process, 7 degree hardware will wedge tight together and as this happens, the installed height will increase a very small amount so it's better to lean on the lower side of target height.


  • Q- Will I need an installed height micrometer to set up the installed heights?
  • A- Yes, in order to properly set up installed heights, a height micrometer suited for beehive springs will be required. It must also be capable to clearing Ford's stepped spring base. The mic must contact the same surface as the spring.


  • Q- We have a beehive installed height mic which we used on another application- will it work on my Cleveland heads?
  • A- That depends on the brand and model of the mic. Some height mics are designed for beehive springs and LS Chevy heads or for aftermarket heads with a large flat spring base. Mics for such applications will not clear the raised "step" on 351C heads.


  • Q- How can I determine if the beehive mic we have will work on a Cleveland?
  • A- Just measure the opening (bore) on the bottom of the mic. If the inside diameter measures 1.025" or larger, it should work.


  • Q- Can I measure the installed heights with a machinist scale, snap gauges or calipers?
  • A- Negative, this is not a viable option for the following reasons.
    Calipers, snap gauges or a machinist scale will only work when the measurement is taken parallel to the valve stem and not at an angle. Since the heads stepped spring base is bigger than the retainer, these tools are not useful for this application.


  • Q- My existing installed height micrometer has a stepped top surface which the beehive retainer enters into and contacts the bottom of the step below. The readings I'm getting are .150"+ more than my target installed height. Whats going on and how do I deal with this?
  • A- This condition happens when an installed height mic designed for larger diameter retainers is used with a beehive set up. On common "cylindrical spring" installed height mic's, the shape of the top of the mic is intended to clear the first step used on bigger retainers. Most beehive retainers are too small for Std installed height mic's and will fall into the counter bore which produces an inaccurate measurement.


  • Q- How do I determine if the top side of my mic will work with a these beehive retainers?
  • A- Just measure the inside diameter of the topside of the mic and compare it to the OD of the retainer. The retainer must sit on the top surface of the mic and not inside its counterbore.


  • Q- Do I need hardened shims?
  • A- Yes. Std shims are too soft and will break down during use. Std shims should not be used because as they wear down, fine metal particulate will contaminate the crankcase oil.


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