Max Lift with Vortec Heads

[street3285]

I recently bought some vortec heads for the small block I am going to build. I have always read that the max lift is .480" with the stock valve springs. Is this true? Or is this only if running a roller cam. I am going to be using a hydraulic flat tappet.

[ElkyZO6]

That is correct for stock springs. They are a smaller diameter spring too. Beehive springs or machine the heads for regular ones are your only option.

[street3285]

Is that the max using a roller cam? Or can I get away with a .500" lift cam since I am going to a hyd. flat tappet?

[ElkyZO6]

I'm not sure, but I would change them to be safe.

[street3285]

It is close, but do you think I will be able to get away using this cam with the stock springs?

http://www.compcams.com/Cam_Specs/Ca...?csid=108&sb=2

What is the deal with shimming the valve springs? Or is that just not the right way to do things?

[ElkyZO6]

The stock springs won't be able to control the valve at those rpm's aka valve float. Read this on shimming the springs. http://www.supercarsunlimited.com/in...gs/springs.htm

If I was you I would run these springs. http://www.compperformancegroupstore...e=SBCNEWValves

What rocker arms are you going to use?
I'm running the same heads on my El Camino, but with a smaller cam so I've been down this road before.

[street3285]

Appreciate all the help.

So you are saying, because that cam will be putting the springs at their max potential, I might experience valve float at higher RPM's? Thanks for the help, just trying to understand all this and learn.

I will be using the factory 1.5 arms for now. I am kind of on a budget, and want to cut back where I can. Eventually, I will change them out to roller rockers. I do plan on leaving the self-aligning rockers with factory press-in studs.

[ElkyZO6]

The rocker studs will not stay at that lift. You can drill a small hole in the boss on the head and drive a rollpin in. I had screw in studs put in mine.

[street3285]

I am not looking to race the truck, or rev it to 6000.... I was hoping I ccould maybe get away with leaving the stock springs, but it sounds I might have to change those out too.

Or maybe step down the cam to this one...
http://www.compcams.com/Cam_Specs/Ca...?csid=107&sb=2
Basically, I am looking for a real aggressive lumpy idle, but still be streetable. Is there another cam you can maybe recommend? I don't mind trading off a little horsepower for this, as it won't be a race truck.

Is a machine shop needed to change over to screw-in studs? Or is this something I can do in the garage?

[ElkyZO6]

I would back down to something like this if you really want to run stock springs and studs.
http://www.compcams.com/Cam_Specs/Ca...x?csid=85&sb=2

Screw in studs will have to be done by a machine shop.