I have the following Lunati Camshaft:

Advertised Duration:279I/286E
Duration @ .050:224I/234E
Lift with 1.5RR: .489I/.479E
LSA: 113

Planning on using the following springs:
Crane Cams Dual valve spring kit PN: 10308
If I take the Installed Height and subtract the open height that gives the max valve lift right? So the installed height is 1.750 and the open height is 1.110, so the max lift is .640 lift, Right?

Not too sure about the Cylinder heads... Money is tight. I do have some stainless steel undercut and swirl polished valves allready so i was going to put those in there and maybe clean up the bowl area and remove the casting flaws. But i would most likely be doing them myself unless i can find someone that will do them pretty cheap.

Do not plan on reving too high, maybe 6500RPM at the most.

Now, if I were to put a set of 1.7 Rockers to get the lift to .554I/.542E would I be hurting power/reliability in any way.

Or would it be benificial to go with a staggered setup of 1.6 on the intake and 1.7 on the exhaust to get lift numbers around .522I/.542E to get a bit more on the exhaust side?

Or should I just go with straight 1.6 Rockers and be done with it?

Someone i knew said that doing that will mess with the geometry of the valvetrain and possibly cause valve float and or reliability issues with the valve train.

Please educate me a little on valve train geometry.


Thank you very much!

 

Using Comp 924 springs as an example because I have a catalog with all the information in front of me. With a recommended installed height of 1.880 and coil bind is at 1.200. Than allows a maximum of .680 lift however you never run lift close to the coil bind numbers. To keep away from coil bind you need to have at least 0.060" between the coils. This means the 924 springs only have an effective lift of .620". This highest lift cam I can find in the Comp Cams catalog that uses 924 springs has .629 lift which pushes the limit on the springs. When you get that close to the spring specs, it's better to move up to the next size spring.

Other things to consider with valve lift is the height of the valve guide. If there's too much lift on the cam, the bottom of the spring retainer can hit the top of the valve guide long before the spring reaches coil bind.

Pushrod length needs to be measured. Depending on the base circle of the cam, the installed height of the springs and the type of lifters used, chances are the pushrods will be the wrong length. Pushrod length checkers are cheap and are well worth the money when building a custom engine.