I have a good engine from a 89 suburban laying around. I came across a set of stock vortec heads. I think they are from a 97 chevy van. I am under the impresion that a guy can get 400 horse from the vortec heads with a well thought out combination. Are all those heads basicaly the same flow wise? does anyone know flow numbers? Are some vortec heads more desirable and if so which ones? How big are the combustion chambers in those heads? How much valve lift can they handle, and how big of a deal is to upgrade them to handle more lift?
 I would be going carburated, what am I up against intake manifold wise? 450 horsepower would be a goal. I want to bump compresion to 11:1, solid roller cam, and maybe a 383 crank...
 Where can I find some articles on buildups using those heads?  

Yikes, that's quite the set of questions, but I will try to get them all...

[statement] 1.) 400 Horsepower from a set of Vortec heads is very do-able, and if you're like me and believe that number doesn't mean much, they're some of the best budget cylinder heads available and the best Gen I head that GM ever put on production vehicles.

2.) No two heads are the exact same flow-wise and that doesn't bother us budget builders. I'm pretty sure that  the majority of Vortec heads used for performance engines are either the #062, #906, or the newer 'Bowtie' versions. I don't have much knowledge on the other vortec-style heads and I wouldn't make any guarantees about their output potential.

3.) Numbers from Car Craft Mag, Chevy High Performance, GM, Stan Weiss etcetera put the peak flow of the Vortec heads I mentioned at around 220-235 CFM at around a half an inch lift (28 inches of water of course), but really what is that number worth?

4.) [answered in question 2]

5.) All the Vortec heads I mentioned should have around a 64-65 cubic centimeter combustion chamber. Of course, just like flow numbers, there can be wide tolerances (probably 2-3 cc) on this number.

6.) The stock valvetrain will probably accept a camshaft of about .420" gross lift, but even this may be pushing it if you're using a faster-than-stock aftermarket camshaft. The forces exerted by stock springs are very small in terms of the force needed to control the tappet speed/acceleration of "new age" aftermarket cams.

7.) If you plan on using upwards of a half an inch of lift then most likely the stock spring pad will need to be enlarged to accept a larger outside diameter valve spring. In most cases the top of the valve guide will also need to be cut down (in height and width) to accept a smaller valve seal that will eliminate retainer to seal clearance issues that limit the lift of the stock setup. If you need double springs the entire valve guide boss may need to cut in width as in stock applications this valve guide boss locates the stock spring on its inside diameter. So it can be a fairly big deal as you need a dedicated cutter to make all these cuts and then you will need to buy new valve seals and valve springs, etcetera. Most leave this up to a machine shop as most people don't have the equipment or the experience in assembling heads (checking spring height and doing these machine-shop style modifications). It's common for many just to order assembled heads from various supplies that are already machined for higher-than-stock lift camshafts. Everybody and their dog is offering vortec style heads now that will be set for .500+ lift out of the box. I would still make sure that the valve springs are at least very close to the recommended springs by the camshaft manufacturer.

8.) As you probably know the best intake manifold on the market for street machines(and it has been for quite some time) is the Edelbrock Performer RPM. Knock-offs like professional products dual plane air-gaps will make similar power and Weiand and Dart for example have other dual planes that will make comparable power. Depending on the vehicle hood clearance may be of some concern as all of these manifolds are awfully tall.

9.) Where can't you find buildups with these heads? Check Car Craft, Chevy High Performance, and Popular Hot Rodding. PHR has recently done a couple of budget 350 builds making 400+ horsepower that are definitely worth looking at.  

From what I can tell you are very knowledgable on this topic, I appreciate you taking the time to share some of your knowledge with a backyard guy such as myself.
 I have been to the websites mentioned and can't find much usefull information on specifics that will help me decide if I want to invest in a vortech head setup. Maybe you could send me some links.
 I don't know where your head is at but horsepower numbers and cylinder head flow numbers are the world to me!!! If I want build a 700 horsepower small block(na) I can't go buy heads that flow 230 cfm and expect to accomplish my goals. With out horsepower numbers and flow numbers what am I supposed to use as a frame of reference for what I am trying to accomplish....
 Everybody and there dog is offering vortech heads that will take .500 lift out of the box....as mentioned above I came across some vortech heads at a cheap price. I have seen them offered at $1000, I would never pay that for those heads! That's just me.
 I wanted to know what the flow characteristics of those heads were because it will help me with cam selection (no sense putting in a .700 lift cam with heads that don't flow for crap above .500) and vise versa small cam with heads that only flow with alot of lift=no go fast.
 guys that are making 400 plus horse with vortech heads,  approx. how big of a cam they usin?
 in conclusion what's the big "3" for the 400 horsepower vortech set up (i would like to make 450) camshaft,compresion,cylinder head?

There are alot of variables on all the topics we touched base on, I was just tryin to get a "ruff idea".....thanks  

Have you ever heard of NHRA super stock? 600+ horsepower from of ports of 160 cubic centimeters, that's smaller than the vortec heads we're talking about here! Flow numbers are not the holy grail of horsepower, if you can use the velocity you can continue to make power...

I guess I would say that flow numbers are not completely useless but the reason they can be so misleading is that there is no hard and fast way of determining how they will benefit power production. The horsepower per CFM ratio is more dependent on the velocity, induction system length, and induction system wave-tuning, which more directly affects the amount of air that can enter the cylinder during one valve cycle. Measuring the amount of air flowing through a port at a constant test pressure at steady-state valve motion DOES NOT closely represent what is happening in an engine. I guess the morale is chasing mass flow on a bench can get you into trouble.

We can determine our own ballpark figures with some common sense and a little know-how of the situation. I can say that you wouldn't put a .700" lift cam in a street engine regardless of how well the heads flowed above .500" lift. This is besides the fact that under actual running conditions flow stall is not nearly as exaggerated as on a flowbench. Referencing NHRA super stockers once again, they are  using lift per diameter ratios up to around .37:1. That is lifting a two inch valve almost .750" off its seat, do you think that the flow on the bench looks great there? Nope! When speaking of these terms it's also important to take into consideration the mass flow of the entire induction tract (intake manifold and carburetor for example) which the average person has little to no information on.

Now, that my rant about flow numbers is over I'll get back to something that may be helpful.

Here are some good articles to take a look at, not all of them may deal with OE vortec heads but they at least outline some good aftermarket Chevy heads to use for budget performance builds. Please take your time in looking through all of these.

http://www.chevyhiperformance.com/howto/97458/index.html
http://www.chevyhiperformance.com/techarticles/148_0507_street_style_vortec_head_test/index.html
http://www.popularhotrodding.com/enginemasters/articles/chevrolet/smallblock/0611em_vortec_small_block/index.html
http://www.chevyhiperformance.com/techarticles/148_0506_gm_bow_tie_vortec_small_block_engine/index.html
http://www.superchevy.com/technical/engines_drivetrain/cams_heads_valvetrain/sucp_0705_budget_chevy_cylinder_heads/index.html
http://www.chevyhiperformance.com/tech/engines_drivetrain/cams_heads_valvetrain/0606ch_cylinder_head_performance_test/index.html
http://www.carcraft.com/projectbuild/116_0310_car_craft_engine_build_comparison/index.html

This would probably be one of the most popular choices for a Vortec head...
http://www.sdparts.com/product/SD8060A2/VortecSBChevroletCylinderHeadwValveSpringUpgrade.aspx

I say that 280-285° cam on a tight lobe separation (probably 108°) 400 horsepower is do-able with a vortec-style cylinder head. Of course this is dependent on if a roller is in the budget because that could free up some added horsepower by means of extra lift and "area under the curve" duration, making your goal a little easier with possibly a slightly smaller camshaft. The 108° LCA coupled with pretty healthy duration for a street car would also require a very effective exhaust system to help scavenging and prevent reversion.

There is really no set value for what the static compression should be, only general guidelines within limits. More compression is more power to a degree. A minimum compression ratio? That's hard to say, all I know is that compression helps retain bottom end power, keeps exhaust velocity high, and improves combustion at all speeds. This all equates to helping an engine out throughout nearly the entire rev range. An engine with "too much" camshaft for the amount of static compression will run very poorly at low to midrange speeds but it's possible for that engine to still make a good peak horsepower number as horsepower is more dependent on how fast the engine can induct and rid itself of combustible/combusted gases rather than how effectively it uses them. Overall, it's just not a good idea to skimp on compression as it costs power and efficiency SOMEWHERE along the line.

With all of those builds I sent you can get an idea on what you want to achieve and how to do it.  

your a real jack-in-the-box  what's your deal???  

I'm just trying to present some information that someone can find interesting and find useful. I'm not a genius and don't expect anyone to learn how to build engines, port heads, or win races by what I say...

Sorry If I'm not very concise.  

I think GibTG has been on his best behavior with your questions.Lots of info and you call him a what!Like I've told one other poster if you don't appreciate the help don't ask.       WIEDER  

whats his name went on a tangent rambling on about all kinds of crap that had notHing to do with the basic questions I asked. All those big words may impress some people on here but not me! Talk to me in plain terms about stuff that relates to the question I posted. and lets stay focused and not go off on some rabbit trail. Save your ego inspired rant about some drag racing class to yourself unless it pertains to the topic. Building a 400 horse motor with the vortech heads can't be that hard. KISS= keep it simple, STUPID!!! LOL!  

If nobody wants to talk about the vortech stuff.... how about that NHRA super stock class (or whatever you keep refering too). Those heads with the 160 cc ports that they are making 600 horse with. Are those 23 degree valve angle heads. how big of a cam are they using. how many cubic inches. how much compresion.  

hey gibtg. you never did clarify. The performer rpm, will that bolt to the vortech heads? There is only 8 bolts for the intake manifold on the vortech heads and they all go straight down....don't know if your aware of that.  

Why should I continue to give you advice?

You tell me, I WANT FLOW NUMBERS. Why am I not allowed to give an example of why I'm not going to go get you a flowchart?

Please continue to be naive and go put 350 CFM heads on your 5500 rpm 350.  

Oh come on now GibTG,before you answer a question ask the person if they want a condensed version or the full report.    WIEDER  

I tried to be respectful...

Please just leave this board alone and go build these engines without our opinions. You should look elsewhere for people of your own ability and skill when it comes to performance engine building.

Even if that skill is of a backyard hack who is grossly uninformed and too ignorant to care about having the right outlook.  

" continue to be naive and go put 350 CFM heads on your 5500 rpm 350"

I thought flow numbers didn't mean anything wierdo.
I would love to have some heads that flow that well.
You apparently want to put some 160cc port heads on a 500 cubic inch high compresion big block spinnin 8000  

Then why in the hell are you continuing to bother me with your presence? All you're going to do is come here and take shots at anyone that tries to help you because they're not up to your incredibly high intelligence level?

On these boards I deal with a lot of people like you. You obviously have issues that you're trying to resolve by talking down to everyone that you sucker into trying to give you advice.

Why would you even ask for your help? You knew long before you asked your question that you think so much of yourself that you would never accept any advice or criticism.