Are there any tests of varius brands of heads for flatheads, i mean take the same engine and test it with different heads, to se wich brand deliver most hp Lars
Joe Abbin's book "Blown Flathead",covers all the popular cylinder heads including several stock cast iron heads. His book shows graphs and charts of flowbench data he has accumulated from doing extensive testing with the installation of larger valves, relieved/unrelieved blocks, port/unported intake and exhaust ports. These results show how each of these combinations are affected by the modifications a person would normally do to their engine, and what kind of gains to expect(or not) by doing them....
A few years ago Streetrodder Magazine did a series of articles entitled one more flathead. One month they compared Edelbrock, Offy and Sharp heads. I remeber they had some flow test results I think provided by Joe Abbin. I do remember they chose the Sharp heads for their build. I'll check tonight and see if I still have that issue. Seems like may have been Fall of 2004.
Don't wanna hyjack the thread but I feel this would pertain to the original question. How about opinions on using old heads versus new heads on a mild street engine? Lets say you have a choice to use an original set of Eddie Meyer heads or buy a set of new Edelbrocks, Offys or Sharps... Which would you choose and why? Would the new heads work better? Cool better? Any reason to not run the old heads? I think the "wow" factor of the EM heads would be better than a new set just because of what they are, but I don't wanna sacrifice reliabilty, cooling, performance, etc... just to run a cool set of heads. Anyone feel like jumpin in?
not to sound like a complete moron but why would aftermarket performance heads perform worse then stock heads? lol theres nothing wrong with the old heads, and youd swap them out for preety much most of the same reasons youd swap them out on any other motor. flatheads arent rocket science its just another motor, also to yourquestion: Lets say you have a choice to use an original set of Eddie Meyer heads or buy a set of new Edelbrocks, Offys or Sharps... Which would you choose and why? isnt that preety much what the referances just posted would answer? its like people dont read before they post even if its just two or three posts
As stated above; just "grabbing" any head; - stock or after market - and bolting it on a flat head engine isn't necessarily going to INCREASE or DECREASE H.P. (BUT; choosing an incorrect head can DEFIANTLY cause a LOSS!!) The factors of fuel octane, compression, cam lift and duration, size of valves, relieved/unrelieved blocks, ported or un-ported intake and exhaust ports ALL contribute to the final H.P. numbers. Plus, many of the after market heads - BRANDS - are designed for different combinations of the above factors; ... so to say ONE is BETTER than ANOTHER, (or worse) is impossible!!
"...why would aftermarket performance heads perform worse then stock heads?" Airflow. Many aftermarket heads achieved high compression by lowering the lid in the area between valves and cylinder...stock heads very often flow more air. Some try to regain that area by relieving...but can that area flow as much as the former area ABOVE the seat? Obviously, there is a tradeoff between compression and flow in a flathead, but it is a complex one because actual compression pressure depends on the degree of cylinder filling...10 to one compression on a half empty cylinder would equal what? Stockers are limited in possible compression on stock size engines, but this deficit disappears rapidly on bigger displacement engines, and of course there are some preferred stockers...and some semi-rare ones designed for high compression. I think that at the higher levels of flathead performance, no one is using any available chamber anyway...if you recognize the outside of the head, you wouldn't recognize the inside. But most of those guys would kill you if you saw their secret chambers anyhow...
indeed Joe Abbin and Mike Davidson's books give results from their flow bench tests using various combinations. again, Abbin said something to the effect, "not one single component is the golden egg, rather it is the combination of carefully selected internals and configurations that'll make ye go faster".
I completely agree that its the sum of all the components combined that creates the best package! What cam works good for Consumer A might or might not work as well for Consumer B & C. I merely answered his question of anyone doing formal testing and comparing cylinder heads. He can purchase the book or research other information and draw his own conclusions and hypothesis based on his knowledge and experience in this area. Joe Abbin doesn't promote one head over the other, or endorse any certain camshaft or other products. Only showing the results he has found by doing and testing these different heads and performing these basic performance mods, letting the reader choose what steps are best for his(her) application.
I swapped heads on my 255 Merc motor. Stock 80cc heads to 61cc Sharp heads. There is a big difference at lower RPMs. No change at higher RPMs.....or not a lot. I run Schneider cam ,2x2s 97s and Headers To be honest .....if you don't have a high lift cam , machine stock heads and regrind the chamber over the valve. If you go 276 or bigger use stock heads.... Or put a blower on top !!!
Hi Tim, I am afraid I don't understand your post and the questions you asked in it. And yes... I did read it as I did with the other posts before mine. It almost seems to me that you did not read my post fully as the questions I asked had nothing to do with which brand of head would make more power (as the first post asked) but if an older head may or may not perform as well as a new head. I was even referenced cooling qualities as a point of concern. I never said anything about stock heads. Why you brought that up, when referencing my post, I have no idea. My point being... Could the metallurgy of an original set of Eddie Meyer heads be less than desirable than new heads? Also, when you consider the new heads being sold today have been redesigned, CNC machined, more knowledge on performance characteristics and cooling passages, better casting processes, ect, etc. create better cooling properties and possibly even a better running engine? My question is "old heads vs. new heads", Tim. Not a "Which head will produce more power?" question. I'm interested in the following info : The pros? The cons? Cooling qualities? Casting quality? NOT stock heads. NOT hp numbers. Opinions offered would be greatly appreciated... even yours Tim. Thanks for reading my post.
You bring up a great part of this equation. Quality of the castings and metal of old heads vs. new. Does this factor into overall performance is something I didn't consider until you mentioned it. I'd be curious to hear thoughts on this as well.
I think answers will vary with heads...looking at the Offy stuff I have, old castings at least look a whole lot better than current ones. Some older heads have a reputation of being made of random scrap aluminum from all sorts of sources, leading to problems when welding damage, odd corrosion...and then there's the possibility of a head that has been re-heat reated by violent engine overheat. But then, probably few original heads paid much attention to metal formulae or charcteristics and depended solely on stout castings to cover engineering thought. And casting detail...some show very crude control of wall thickness, some are like jewelry. Weiand "cheater" versus real Ford Canada heads illustrate this nicely...Weiand shows HUGE variation and offset in thickness control, poor surface detail. I think you just have to look over the head in question and make a flying guess from the charcteristics you can see. Much easier than testing til failure so you really know...
i think ya get what ya pay for....i would prefer a new head of mediocre qualty over the same item with 50 years of corrosion and abuse. new offy's for one, the gasket surface is rougher than a cob and the plug is buried 4 or 5 threads deep, only 2 c/r's available etc, if you are gonna have to rework it why take a chance with one that may have been overtorqued or overheated. one would like to think the quality of aluminum used has improved ,but it would take a metalurgist to make that determination.
There is no doubt that knowledge of metallurgy has risen, casting & foundry procedures are better, and in general quality is up from old to new heads. However, then as now, some heads were better quality than others (due to this "lack" of knowledge back then). Talk to folks who have repaired old heads & see which ones weld better if you're interested in the actual metallurgy. Otherwise, if it bolts on & seals fine, the metallurgy should have very little to do with performance. AFAIK, the only modern old head that's been redesigned is the Edelbrock. The quality (mainly in consistency) of their castings has improved dramatically in the last two years. However, on Joe's flow bench, they actually lost ground (albeit at the upper RPM ranges & not a lot) compared to their old originals. I think the advantage of CNC machined chamgers is consistency, not chamber shape/design. The Offys are still using cast chambers & are notorious for requiring work to get the chambers consistent across the board... There are plenty of old heads that are good out there. However, as has already been mentioned, for best performance, the components need to be matched. I've run both with good success. On the average hot street flathead, it's hard to tell much of a difference between the heads...most are such an improvement over stock (generally speaking) that differences between them are small. If you want more than internet rumor, call John Lawson or Joe Abbin - both have done a lot of flow work & dyno work.
WOW! I greatly respect the opinions of all who have chimed in on my questions. Thank you very much for taking the time to express your thoughts and knowledge.
The article I refered to earlier concerning aftermarket heads was in the July 2004 issue of streetrodder Magazine.
The Jalopy Journal
