???why 516 heads

[dirty dan]

I dont under stand why I keep hearing about the use of the closed chamber 516 heads. They will boost comprestion I know. Comp;is a needfull thing . However the 516 have very small valves. Beneath the valves the bowl area is also very small. This will give a big block asthma. This is a VERY BAD thing for performance. all engines need air the more the marrier. Thous resone for blowers and turbo`s. The size valve in the 516 would work GRATE if you could squeze them into a small block aplication,but not for a big block. If you are thinking of puting larger valves ia 516 .Dont wast your money. The bowels are cast to small . If you open them enough to handle the flow of a 208 and 174 valve combo; you would be so close to the water jacket you wouldn`t have room to sneez without causeing a crack or a leak. In the end you would be about $500 lighter and only have the same size valves that came stock on the later model heads. When mother gave us the 68 magnum engines,we got 906 heads wich were spectacular.But only because they flowed so much more air. To do this it was nessasery to open the chambers. That did reduse comp; but it also gained :HP: In1968 regular gas was 94 octane mediem grade was96 and prem;was 98-99 depending on whose gas you bought. So not so cheap whimp gas was not the resone for the lower comp; think aout it. thank goodness mother never went back to the 516. Instead she gave us a wider selection of biger valve heads. They all came with 208 intake and 174 exhaust. the casting #452 are the best production head around for the average $$$man. If you freshen up the valves and bolt them on you will make more :HP: then the 516. And I that is without any porting at all. If you are in dout of this then take a 516 and a 452 to a speed shop that has a flow bench with an experianced operator . The # tell the storie better then I can.

[rumblefish360]

Is this a response to a question? Or a statement in found info?
Neverthe less, the flow numbers of which you speak are truly the bottom line.
Ahhhh, the days of ol' when real gas was purple.

[Stoga]

The 1967 915 big block head, was in between the 516 and 906 in design. It had the improved intake port and larger valves of the 906, yet still had a closed combustion chamber like the 516. These heads are very desireable, and you will pay a premium, when you find a good set. The 516 is really an obsolete design, almost impossible to get much improvement without a ton of work. You're much better off starting with any later head than a 516. The improvement in compression ratio is more than offset by the inferior flow compared to the later heads.

[gsmopar]

There is a set of NICE 915's for sale. Look at the thread "Indy vs. Edelbrock vs. Mopar"

Later,

Greg

[Tarrbabe]

I keep hearing everyone put down the early heads and statements that they don't flow well. The thing is I have never seen anyone post flow numbers from a heads up test on the heads. Anyone want to post numbers? I have a set of 200's and they have the 2.14's and 1.81's so they will fit without going through the water jackets. It is really hard to get information on older heads. I read a lot of people putting them down but what about facts?My heads have new bronze guides and triple springs. If I had more FACTS I could make better decisions. Thanks.

[dave571]

I went with the 516 casting because of the closed chamber, and the better flame propagation of a closed chamber design. This is known fact, and seen in modern performance heads.

I also talked to several head guys and got thier opinions, that they flow more than adequately, and even an old time racer who swears by them.

I have no flow numbers to provide.

I also read info in an artical called "Cylinderheads part I" at moparmusclemagazine.com.

It explained in very clear terms that virtually all the "open" design (906 and newer heads) flowed nearly exactly the same, and that the open head design was brought in for emmissions reasons only. No comparison was made to the pre 66 heads in the article, but it was mentioned that the runners in the 915 were a step forward from the earlier heads, and the 906 was pretty much the same head, but with the open chamber added for emissions reasons. The article provided no info on the 516, but certainly raises questions about the much revered 906.

I port matched and mildly ported the heads prior to engine assembly, about 30 hours of grinding time total with carbide cutters. The engine is in, and makes very good power.

I'm not saying this is the way to go for every one, or that there is no other way. I would be a fool to do so, after seeing the results people have had with other heads. Many guys on this board can attest to the success they've had with 906 and newer heads. There are many examples of very impressive results.

Equally it would be very foolish to say that the exhaust valve size of the head 516(1.60") is a limiting factor, since there are many brand x engines that make very good power with a 1.60" exhaust valve.

As I've stated before the SB 427 cid crate gm motor, that makes 500hp uses a 2.08 intake and a 1.60 exhaust. Same size valves that are in the 516.

Also in the current HotRod there is a story about a naturally aspirated Dart/gm 560cid big block that makes over 1000 horse power by 6000rpm. The engine is a full race engine, the cost of it, not provided, but I would guess in the neigborhood of $30000. The exhaust valve in this motor? 1.80". Hardly seems like enough, but I don't think anyone can dispute the outcome.

I'm not slagging the newer heads, but I am saying that there is more to performance than big valves. and that perhaps some thoughts on the early stuff needs to be rethinked, prior to saying it's no good. Nobody knows everything and new theories on performance seem to arrive all the time.

I would be interested in flow number comparisons if they are available(not that they'd apply to ported heads) but they do give you a base line.

I also used 516 heads, beacause I got them for free

[goose]

Mopar Action did an article on head flow numbers about 3 years ago, they tested the 516 as well as a few open chamber heads. When equipped with the 1.74 exhaust valves the 516 flowed just as well as the later heads on both intake and exhaust. The article was written to evaluate the MP pocket-porting templates on a variety of heads, so they also have numbers for all the heads after being ported by using the templates. I can get the flowbench numbers from the test if y'all are interested.

[rumblefish360]

I am goose! Post away! Lets see'em.

[gsmopar]

Ditto

[Tarrbabe]

Goose, I'd like to see the flow numbers too. Did you find them?

[goose]

I will post them tonight; I didn't get home until way late last night because we ended up painting my pal's Charger unexpectedly. Not that it wasn't worth it, 'cause it looks kick ass.

[goose]

I have apparently misplaced the magazine that mentions the flow numbers... it will take a couple days to find it, so please bear with me

[six pack]

Chrysler went to open chamber design in 68 to PROMOTE flame propagation. This was the so called emission head only because it burned more of the fuel than the closed chamber design it replaced. If you burn more of the fuel, you make more power, simple physics.

Newer engine have swirl technology built into the design of the ports and chamber and cannot be compared to old castings from the 60's.

For a stock looking engine give me a set of 452's any time.

My 2¢:

[dave571]

They talk quite a bit about swirl and flame propagation in the article at moparmusclemagazine.com.

Is there some sort of reference source anywhere, that says open chambers have better flame propagation? If there is, please let me know where I can I find it, because I would be very interested in reading it. I know there are sources that say they are better for having lower NOx emmissions, because of the lower combustion pressures that are produced.

If burning more of the fuel makes more power, and it's that simple, then why did the smog motors of the early 80's make less power, yet burned the fuel more completely? That's what lower emmissions is right? The fuel is burned more completely reducing co, co2 and hc emmissions?

[Tarrbabe]

Six Pack, ------ swirl ports in stock BB heads? Are you drunk? Mother never made any production big block heads with swirl technology. At least none that they ever advertised AND flame propigation depends on the shape of the piston, of course most factory pistons are flat top and that should go along with your generalized statement. From all the info I have read (and I have never read the flow numbers from all the B heads) the ports were improved in 63 and no changes were made for flow enhancements until production of the production head ended. The only thing that was a major improvement was the addition of hardened exhast seats for no lead gas. I just got thru going thru all my old articles and pretty sure of what I say. If I had a scanner I would post ALL the articles.

[Stoga]

He didn't say that, scroll up and look again. Swirl ports didn't come on v8 Mopars till the Magnum series in the early 90s, IIRC. And I will say this, cause I got the opportunity to flow a whole bunch of stock big block heads, and in unmodified condition, the 66 and earlier heads, are very deficient in flow compared to any big block head that came after. This does not include Max Wedge or Hemi heads, of course!
Many newer engines do have swirl port build right into them, just as six pack said, I don't think any production big block heads ever had used that technology, just open and closed chambers. The problem with the early closed chamber , is all the edges, along with the higher compression ratios, promoted hot spots and spark knock. With Chrysler, as most of the industry, knowing poorer gas was coming sometime in the future, I expect they stopped using the close chamber heads more for that reason than anything. There are a lot of sharp edges and casting flash on an unmodified closed chamber head. With an open chamber head, you don't have that one sharp edge going across the middle of the combustion chamber , to glow nicely red hot and promote pre-ignition.

[Tarrbabe]

[QUOTE]Originally posted by six pack
[B]Newer engine have swirl technology built into the design of the ports and chamber and cannot be compared to old castings from the 60's.

Stoga, maybe six pack didn't say that but the implication was clear to me. The thread is based on technology of the OLD heads and why some want them and his generalized statement that they can't be compared to newer castings was what I confronted him about. That is what we are talking about and I don't feel his statement was productive to the discussion as his clear dislike of early heads led to his statement. Old and New heads can be compared in an effort to help others to decide if they might want to use the older heads or go for something newer. That is why we were looking for flow numbers. I don't know what the numbers are and that is why I posted originally. I can't afford a set of B-1 heads now and don't plan on even building a bb soon, but I do plan on it. I am looking for knowlege and have learned from the input of others in this fourm and hope to continue but I also think that un-truths should be challenged so as not to become taken as fact.
If I was out of line, I'm sorry but I feel his statement was misleading. Maybe not wrong tech. wise, but misleading.



But then I always did like to stir up things to help get a more active discussion going. Nothing gets people talking more than controversy

[Stoga]

[i]



But then I always did like to stir up things to help get a more active discussion going. Nothing gets people talking more than controversy [/B]

Oh, but I've never done anything like that !
They can be compared, but the newer heads do have a lot of technological advances, especially the small blocks. But I have to say, I went back and looked, and I can't see where six pack said anything about big block heads having swirl port design. He explained about the open chamber they started using in 68 was for better flame front propagation, but thats it. No biggy though, discussion are what we are here for. I do know some folks have made pretty decent power using modified 273 heads, it could be that Mopar stumbled accidentally onto something with that combustion chamber design, despite the small valve size and intake runners. I remember something about those or another Mopar head having a stepped port floor, which in retrospect, may have introduced some swirl to the intake flow. I wish Mopar had tried some of these new ideas on big blocks too, but that was most likely, out of the question, after the gas war of the early 70s. I didn't think you were out of line, I was just questioning your observation. Sorry If I gave that impression.

[roller cam]

I Have a 69 roadrunner that is 3300 lbs. I run a pair of 516's on my car. I got it to go 11.29 with those heads. They have the 2.14,1.81 valves it them. they been flow benched and had port work done to them.They were on a 503' motor. the cam I ran was mopars 590 cam. These heads had a bad valve job and the guides were shot on a couple of them. So im sure I could have been in the 10s.

[Tarrbabe]

Nowhere in the discussion was any mention of swirl technoligies and that is right as no swirl was available at that time. That is why I said what I did. Swirl doesn't come into the pix unless someone can figure out how to port them in such a way to induce swirl. That is why I posted. I have read everything I could on the BB heads and and nothing is mentioned in anything I've seen associated with the port design after 63. If anyone has anything on this subject, I would love for them to post and give details. Like I said, while he didn't mention in the same sentence, non-swirl and swirl heads with conection with the BB heads, the implication was there. What I and I suspect most others want is cold hard facts and we can judge from there. Thanks for the opportuinty to post and voice my thinking but most of all thanks for the chance to learn from others. .......Bo
By the way, you mentioned intentional miss match of ports. Do you remembr the Smoky Ram Intake designed by Smokie Yurnic (not sure of the spelling.) The ports were mis-matched and instructions said not to match ports. I never saw the instructions, but Eddie Kanter told me about it in the 70's when I worked with him at his speed shop. I helped him build a dirt track car and we ran it at Oak Ridge, TN. Car ran well.

[six pack]

Thanks Stoga, I think were probably on the same page

My comment of swirl port technology was in reference to the late 80's and up small block cylinder heads.
The problems with the closed chamber heads in the comparisms I have read deal with the fact that the fuel does not burn properly in the quench area of the chamber(between the piston and the closed part of the head). If you have a way to mix this properly, the situation improves(swirl port design).
Are we talking about a great deal of power to be gained? No definitely not, but there is a gain. Before you wip out those comparos now remember that the compression ratio will have to be equal for fair comparism between two cylinders.

Oh and Tarrbabe, I'm sorry you didn't think my contribution was benificial for this thread.

BTW, anyone wants some 516 casting let me know, they all go for scrap up here

Hope this helps

[Tarrbabe]

six pack, Thanks for everyone for your offer to help any who want a set of the "junk" 516 heads. Some may take you up on it and you may be able to make a little money too.
I still take exception to your mentioning swirl technology with the BB heads as there is no conection. I also take exception to your saying there is no way to compare early heads with the later BB heads (if that is what you meant).But you must admit you were the one that mentioned it in or out of context.
Yes you are right about the flame propigation being increased with the open heads. With the advent of open chamber the use of the term of squish area is not mentioned as often. The purpose of the squish area is intended to force the fuel/air in closer to the spark and with the PROPER spark the fuel can be ignited for a larger and quicker ignition to provide more power. Yes you still have the small amount of gasses in the quench area that are un burned at that time but as the piston moves, the flame will continue to the rest. There are good and bad parts to anything mechanical but then you just have to design your application to meet your parts.
Yes the heads in this thead can be compared and that is what I and others were trying to do.
Thanks for your in-put. Sorry if I miss understood your intent.
..Bo

[dave571]

Swirl

Go to moparmusclemagazine.com

click on "cylinder heads pt I" It's in a rotating header toward the top of the page.

The article is long, but the topic of swirl comes up, and the swirl characteristics of the 915 casting are mentioned specifically. They are comparable to modern designs, probably by accident, but they are none the less.

I'd set up a direct link if I knew how, but I don't. Read it!!

[Stoga]

Just post the link in the your reply area, and make sure the box underneath is checked for Automatically parse URLs.

http://www.moparmusclemagazine.com/e...le.jsp?id=5115

I plan to go back and read it, thanks for the info, dave571!

[DartGT66]

Have to add my 2c's. The BB production heads have good swirl properties, so you might call the swirl port heads. They are propably not designed to be swirl port heads, but that's what they are kind of.
I have ported mainly the newer open chamber heads and only one pair of '516' heads. Treating them the same way as the newer open chambers I "found water" in the exhaust bowl between the valves.

[goose]

Sorry I haven't found the article yet... I know what magazine it was and can even remember the article title! "25 horsepower for 20 bucks" or maybe I have the numbers reversed but that's the title.

As far as swirl goes, one aspect of closed chamber heads that improves combustion is the quench area; when the clearances are set up right the air/fuel in the volume between the top of the piston and the quench area of the head are squeezed out at high velocity as the piston comes up towards TDC, this high velocity jet promotes turbulence in the combustion chamber and enhances the mixing of the air/fuel charge. It has nothing to do with any swirl effect of the intake port however.

[Tarrbabe]

Stoga, thanks for the info on the heads. That is a good article and refreshed my memory on a lot. Too bad it didn't cover the PRE 67 heads. I know the J (63) heads were the benchmark and the 67's superseded them. Like I have posted, I have a set of the J's and really want to know more about them. Thanks again.

[dirty dan]

Ihave read through all the reply`s to my statments on the 516`s . I think some of you are missing the point. and some got the message. The reasen for making the post was to share info that I have collected from personal experiance . I read were someone said If you put 174exhust and208 intakes in a516 it would flow the same as a later modle head. I wounder what kind of aditional portting was done to acomplish this. In this case simply putting a larger valve over a restrictive bowl will not incress the flow. Also if you install larger valves such as 2.140intake and 1.81 exhust in 516`s you will find that there is yet another flow dampener. Wich is the chamber it self , shrouding the the intake so badly you are forced to open or enlarge the chamber to enhance flow patterns . Wich will drop the comp: in a hurry. I also read were some one wrote about the 915`s I can not comment on them as they are to much money and to hard to find. And most of all I have no experiance with them. I read the comments about numbers. I dont put alot of stock in compairing flow # unless the test is done on the same bench by the same operater on the same day and at the same vacume and the same lift. and the same and thesame..... Ithink you get the piont . There are just to many veriables for them to be acurate. besides flow numbers are only a tool for making improvements in flow number comparances. What is the one thing that draws you guy`s to the 516?? In the end isn`t it the comp:? Well I know of alot better ways to get comp: thats easy enough to get with close dimentions,why sacrafice flow for comp: that makes as much sence as putting a 2barrle carb on a 440 just because the shiney air cleaner fits it better . Think about it.

[Mills]

Goose is right - I remember that same Article. It was in a Mopar Action Tech Special. The 516 Head, when equipped with a 1.74" exhaust valve, did outlflow the 906 (both heads stock). After the MP porting template was applied to both heads - I believe the 516 even gained more flow over the 906.

I have the book @ home and will bring it to work and post the results.

Mills

[dirty dan]

How can you call them stock. if you have to put biger valves in them. TO make them flow as well as a later modle head. If you have to spend the money for biger valves, why not spend it on biger valves in a head that already flowes better in stock configuration? In referance to the last reply to this thread. READ WHAT IT SAYS! (If you put biger valves in it.) It will only flow as well as a later model head that comes with biger valves already! Again I say Take the later model head and put even biger valves in them and enlarge the bowles biger then posible on the 516`s WITHOUT goig into the water jacket, and you will be miles ahead of any 516. Dirty Dan will say no more on this subject. But if you come see me on race day With an equally preped short block and the same wieght car and gear. if I come with 452`s and you come with 516`s It wont be me at the top end of the1/4!! ( Have a nice day )Dirty Dan