Max Lift with Vortec Heads
 

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.

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.

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?

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

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?

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.

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.

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.

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?

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.

I have the small thumpr flat tappet cam in my mild 350 with rhs 1.94/1.5 vortecs. it is all the cam you can stand in a daily driver. it is even kind of a pain in the ass with my 6 spd and 3.73's because it wants to buck the car at light load cruising. it runs and sounds great, but I would not recommend the larger thumprs unless you have 400+ cubes.

How is the idle with that cam?
What do you have done to your heads? Are they completely stock?

The truck will have a 700R4, and eventually 3:73's.

the idle is pretty radical...along the lines of a 305 magnum from comp.

heads are aftermarket vortecs from racing head service in memphis. they flow a nice bit more than stock and have the correct comp springs and screw in studs/guideplates as delivered. compression is 9.5:1.

it will work fine with an auto. if you use a lock up converter, you will have to experiment with lock up points.

Anybody know of a good machine shop in SoCal, where I can have the machine work done needed to install screw-in studs, and non-beehive springs?

You can use LS6 springs and comp's 787 retainers as a cheaper alternative.

Sweet.... I will have to check that out. Maybe get some exact part numbers from you.

If that is the case, then all I will need to do is switch over to studs. I am assuming I can still use the self-aligning rockers I have.

as long as you do not use guide plates. guide plates and self aligning rockers do not mix.