915 head question

[MOPOWER871]

Question ? , what is the maximum safe valve lift on a 67/ 440 -915 head in its stock form.thinking of possible cam change and didnt want to pull heads.and i dont want coil bind.nothing wild something a step or to up thanks mopar gods

 

[Meep-Meep]

Rather than focusing on lift you should focus on the LSA as that more or less decides the power band of the engine. I'm running a .455" lift cam in basically the exact same car and it runs high 12's in the 1/4 (440 with 10.1:1 CR). Any cam much over stock will require a valve spring change anyway.

 

[383man]

Anything over .500 lift is going to be a problem. Thats when retainer to valve guide can get close to hitting and machine work will need to be done. Under .500 is usually ok for retainer to guide clearance. Ron

 

[440 Cuda]

Camshaft

I have this in one of my 1969 440 'Cuda' cars.

#3412004 {Older Profile}

Lift........... .484"/.484"
Duration.... 284*/284*
Overlap...... 68*
LSA........... 108*

Absolutely 'no problem' with this Camshaft {Hydraulic}. And the stock 440 HP Valve Springs work fine.

Monster Mid-Range pull, and scary 'Power' on the Top-End.

Note: Do not go over .500" Lift with Stock Valve Springs. Coil-Bind will start to develop at .510" Lift.

 

[67 coronet]

just a quick question.why a cam change and how old are the springs you are planing on reusing?really old springs can break if you change the lift.they get very used to doing the same thing for many years.its fairly cheep insurance to change them.

 

[440 Cuda]

Stock 440 HP Valve Springs

* Dull Red Color
* Single-Coil {Heavy} w/Damper
* Installed Height....... 1.86" {Spring-Load Rate = #108 lbs.}
* Valve Open Height... 1.40" {Spring-Load Rate = #256 lbs.}

 

[383man]

just a quick question.why a cam change and how old are the springs you are planing on reusing?really old springs can break if you change the lift.they get very used to doing the same thing for many years.its fairly cheep insurance to change them.

Did he say he was using the old springs over or did I miss that ? Because when I had the MP .484 cam in my 383 I used a Crower or Comp single springs with a dampner. Kinda looks close to stock springs but stronger and work good with the .484 MP cam or any about the same size. And there was no coil bind problem since they were a single spring that worked nice as a srtock replacement spring but strong enough to work good up to .500 lift and even a bit more. I used a spring just like it on my old 340 that had a .510 lift cam and I twisted it to over 6500. I can tell you also with the MP .484 cam on my stock 452 and 906 heads it only had about .030 clearance between the top of the valve guide and the bottom of the spring retainer at full lift of .484. And that was without the valve seals on it. I have heard some guys say they got away using the .509 cam on stock heads but unless they changed the springs and stock retainers by my math they only had about .005 clearance or in that area between the top of the valve guide and the spring retainer bottom at full lift. Ron

 

[440 Cuda]

Valve Spring Information

440 'Six-Pack' and 'Six-Barrel'

* Installed Height.......... 1.86" @ #115 lbs.
* Valve Open................ 1.37" @ #310 lbs.

These are 'stock' Factory Valve Springs, approved for clearance up to .490" Lift, without any modifications
to the Cylinder Head {Valve Guide Boss}.
-----------------------------------------------------------------------------------------------------

440 HP

* Installed Height........ 1.86" @ 108 lbs.
* Valve Open.............. 1.40" @ 256 lbs.