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Stock sbc 462 head flow

16K views 20 replies 12 participants last post by  stock z/28 
#1 ·
Can anyone tell me what the 462 head flows 2.02/1.60. I switched up to the 70cc perf rpm heads and they are 170. Just curious how much the changeup is.
 
#2 · (Edited)
A stock 462 flows about 195-205 CFM @ 28" (unless it's on a super stock racer and then it somehow gets much better while appearing stock.)

The 170 number for the heads you bought is intake runner volume in cubic centimeters.
My database of head flow has the Edelbrock Performer RPM aluminum head (70cc chamber) flows 235 cfm @ .500" 236 @ .600"
 
#5 · (Edited)
I think that's about right. I don't use those heads any more and I concentrate more on cross section than volume. For example if you just port match a head you increase the "burrette volume" but it won't effect the peak port velocity.

I might also add that the intake manifold is really part of the runner when it's ultimately bolted together. The total runner volume is much greater.
Flow testing a head and then flow testing with the manifold attached will sometimes give you surprising results.

For inertia ram tuning, the total runner length is important. This is the length from the intake valve to the plenum chamber.
The second harmonic is the strongest. You can solve for optimum runner length in inches for a second harmonic pulse tuned to coincide with a specific rpm by this:

132,000/rpm

Example: 132,000/6,000 = 22"

That's almost 2 feet! I don't know if you remember the old Mopars with the long outboard cross ram runners, but that was an attempt to capitalize on the ram tuning effect. Hence the Ramchargers, name.


Less stronger pulses are the 3rd and 4th harmonic but they require a shorter runner.
Intake valve closing point is critical to take advantage of the inertia ram effect.
 
#6 ·
Paul, I know this likely sounds stupid but I'm sure I read somewhere that the longer the intake runner the lower the peak power RPM...does this sound right? I'll have to see if I can find the article I was reading and post it...
 
#8 ·
Hi guys,

I really dont know what the 462 will flow. I guess you would be talking at 28in and .5 valve lift?

I think the 165cc is pretty close but in my experience they are generally less than that.

You know, the super stock heads dont really appear very stock anymore most of the small blocks I have seen have exhausts raised and are "D" ported. The intakes are are raised as well.

The Stock Eliminator heads are supposed to be stock, but there is considerable work done. Still not much to look at compared to a Dart-World-AFR-etc..

My only thought on both the Super/Stock and Stock cyl heads is basically this and just my opinion----- I dont like to look at a component (head Manifold- etc) in such a limited mind set. If I see engines making a lot of power and more importantly cars going fast, using "limited" parts, maybe the technology that they are using if applied to other classes would have benefits.
The attitude that to get "X" horsepower you have to have 14 to 1 compression and a 230cc head, may just not be true. Having the basics of the engine right is much more important to me than just throwing parts at stuff. I just enjoy trying to get as much out of as little as I can. I know that attitude is not for everyone, but I have found looking at the technology and theory that these (S/S-Stock) type engines use, if applied to "standard" automotive engines, show amazing benefits.

I have seen something as simple as cyl wall finish and ring package improve a bracket car .3 sec.. Its this type of thing I enjoy. Im not real big on "killer Parts" unless you need them.

Sorry to ramble and I wont mention Stock or Super/ Stock stuff here again (Promise)

Good luck
Jeff
 
#11 ·
I read an article on the difference between Pro classes and bracket racers. If you offered a Super Stock or Pro Stock racer a part he could bolt on and increase output power by 10HP it could be worth an almost unlimited amount of money. The average bracket racer could give or take 10HP and never miss it as long as the car stays consistant. The same article talked about a 67 BB Super Stock Camaro the owners had flow benched over 100 intake and head combinations trying to increase HP.
 
#12 ·
I read an article on the difference between Pro classes and bracket racers. If you offered a Super Stock or Pro Stock racer a part he could bolt on and increase output power by 10HP it could be worth an almost unlimited amount of money.
When we were full on, knee deep in our prostock truck engine developement it was costing us about $10,000 per hp after we got our good baseline engines up and running. One of those engines were $87,500 and you had to buy two. We wouldn't sell just one. You also had to sign a non-compete clause. One engine would be being upgraded, while the other was running. You paid for all of the upgrades along the way, if you wanted to keep up. So yes, 10hp would be pretty spendy. A current prostock car engine is just about priceless, because nobody will sell you one. There are a few major players in that game, and they all lease the engines. You show up at the race, get your engine, put it in, race, and it comes back out and goes to the guy you leased it from. Most of them will provide you with a test engine if you want to go test somewhere, but it's not the good piece.
While i like the ingenuity that goes into the stock/super stock cars, I would much rather just buy good pieces to begin with and not worry about. If you saw what went into a national record holding A/SA you wouldn't believe it. They are very fragile pieces. I would hate to even try to imagine what it would cost to have someone build one for you. Probably in the $50,000 area, just to guess. All that to make 600hp or so? I'll take the "new" parts for 10 times less.
Much of what goes into a good stock piece is also utilized in your local circle track late model cars. Non ported heads,intakes,and flat tapped cams. All silly rules that do nothing but drive the price of the engine up. One of my good late model engines will run about $25-30,000, depending on parts. Absolutely silly,but the guys that want to win, are willing to spend it. I guess i've gotten a bit of track here. So I'll stop now. :)

shawn
 
#13 ·
Hi Shawn,

Again I really dont disagree with anything you have said.
I dont know what your buddy has in his a/sa car but I bet its very substantial, but I guess its what he wants. I bet he got a "tremendous" sence of satisfaction when he set the record. I know I would have.

Im not trying to get anyone to do much of anything, just not to wholesale discount what basically simple and plain components will provide when properly (and sometimes very cost effectively) prepared and/or applied.


To get away from the engine issue I will try an use the suspension/chassis as an example. I get a lot of guys asking about 4/link and ladder bars. I dont really know anything about either. When I ask how fast they are going to try and go, its usually not all that fast. I suggest they look at how quick a properly set up car can go with a Cal-Trac type bar and a 9 in tire, with little or no major chassis mods. I have customers who are very happy in 10-- 10.50 range with this set up. If a guy wants 14 in tires and 4 link its ok with me, but it dosent mean he had to have it to run 11.20s.

This chassis learning stuff dosent really apply to me at all because I know nothing about it and dont really ever do any work on them, but I think the learning curve from "having" to use a 9in tire and traction bars has been valuable to a lot of people.

One of the neet things about most class type racing is its very cause and effect oriented. Most changes have an effect and what you can learn from that in my opinion its very valuable in other forms of racing as well. I know that info I have learned in stockers has been a major benefit in circle track motors as well as budget street motors.

I would hope the effort that you put into your Pro/Stock Truck produced some valuable knowledge that could be applied to other type engines as well.


Looks like Im rambling again sorry

Jeff
 
#14 ·
:D Guys I love the rambling!!!!!! thank you Paul for the specs and the tune up on what I thought I knew:D
Jeff, I like the Super Stock input you offer as improving stock components and perfecting the whole build process really makes you appreciate the time spent putting it all together.
I think I'll spend a little more time on the science of my motor.
 
#16 ·
Many years ago back when you could buy a car with some power some guys pulled the new motor out and sent it off to have it blueprinted. All the same parts were basically put back but everything was corrected to precise tolerances. I had a friend who bought a Niki Nova 350/350 with a 400 Turbo and a 4.11 gear with headers brand new. It ran mid 13s just the way he bought it and that was pretty darn quick back then for a daily driver. He jerked the motor out and had it blueprinted. When he got it back it would run high 12s which was incredible at that time. Stock motors are mass produced with lots of fudge room so tightening up that fudge room and getting everything corrected to it's max potential will really help any motor combo. All the best parts available are nice but bolted onto a non blueprinted motor won't give you the best bang for your buck. Rules classes are very expensive because someone is spending a ton of time looking for a edge that's legal or done so well it can't be detected by the tracks Techman. The crooks have more time to be crooks than the cops have time to be cops........LOL. RM
 
#19 ·
I would hope the effort that you put into your Pro/Stock Truck produced some valuable knowledge that could be applied to other type engines as well.
Absolutely. The "trickle down" effect works very well. In fact, huge advancements have been made in small block,drag race technology because of the truck class. Even short lived as it was. It gave people a bunch of money to spend on developement that would have taken much longer to do, given the budget's of most people. Just so you know, I don't disagree with what your saying, either. I think the problem is that people mistake "developing" a combonation based on the parts they can use, and just bolting them together and expecting the same results. For most it's quicker satisfaction, and much cheaper, if they utilize current parts then trying to "message" a 35 year old part into something that is was never designed to be. I take a lot of pride and satisifaction in the fact that we make the power that we do, with the parts that we have to work with. That being said, I wouldn't recommend someone limiting themselves to a "stock" type part just because John Doe went 9's with his A/SA car. Most guys here, at least I don't think, race cars that have specific rules like certain head casting, compression and such. I would much rather seem one of them go buy a new AFR head, and get something that just about insures good results, then try and revive those old '292 heads that have been under the bench for 10 years. I HATE working with that old junk. You never know what your going to run into. Casting flaws, holes, cracks and the list goes on and on. Again, I'm not saying you can't make good power with it, but sometimes your just throwing good money after bad.
shawn
 
#20 ·
Hi Shawn,


Again basically I agree with you. I never try and limit someone on components or technology. I my opinion you should always use the best and most effective means possible in a competitive situation.


I would never suggest that someone put hours and hours of work into an 041 (as an example) when a off the shelf 2oocc Dark would work as well or better out of the box.

I don't mean that someone should should even try to use an old stock type part when new parts are a better value. Its the criteria that is used in condemning the basic design and function of the original part. If a guy can make a "junk" part go fast, then if I can understand how he did it and apply the basic technology to the modern part, I will be much better off.


I know you and I agree and most of this is just semantics.

I just really like class type racing technology.


Jeff
 
#21 ·
Hi Shawn,

After reading your other post on the Vortec thread I thought I would add this to help clarify my thoughts.

Im very impressed with with what you have accomplished with this "limited" engine. In my opinion this is very comparable to Stock or S/S style engines.

The creativity and the precision in which these must be built and the results are what impress me, not the engine components.

I will use the heads as a quick example. I dont know what the Vortecs will flow out of the box, everybody benches are a little different and its kinda like a dyno, its understanding what you are seeing thats important. So the flow is really not my point here. Its the fact that you were able to take a "budget" and apparently "unmodified" head and make it perform much better than its generally thought to have the capability to do. "Maybe" a bigger port Dart could achieve the same power (and more importantly be as competitive) at less cost. But what if you took the same "technology" and applied it to the Dart casting? Im sure it too would show dramatic improvements and still be a "stock" part.

I totally agree the engine you describe would be a very expensive piece to develop build and maintain, kinda like a Stock, or Super Stock combination.
In my opinion its someones ability to pay attention to the details (and the ability and/or equipment) to "modify" the details that make a difference.

To further my example, lets say the sanctioning body that provides the rules for this class, finally shows some common sence and says that you can now use an off the shelf AFR head,that they have ported and provide. How long before this "cost saving head" would come under the same scrutiny that you or I would provide to the original heads? Unless the heads are actual "spec" pieces and sealed, the sharpest guys are still going to have the capability to provide the most competitive combinations.

So it really comes down to the same thing in my opinion, dont underestimate how much air- torque- hp- (pick a spec) that a part or a combination can provide, because someone will drive around you with "junk".

Its a cost versus performance thing at most guys level, and I really believe the best value for a person may not be just to throw the "biggest" part at something, unless they just want bench racing, bragging rights.


Geez Im really rambling now

Thanks
Jeff
 
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