Looking at the overall picture here, a 2x4 is worth 4 hp and about 10 ft pounds over a stock four barrel... For the price they go for I think porting the single four factory chunk may be the way to go My impression and opinion is that either the few aftermarket parts available for Nailheads are primitive, or original factory parts were very well designed and/or the engine just doesn't have much left to give after a good quality rebuild. Maybe a little bit of all of the above. I'm not a knowledgeable Buick guy, but just looking at it, the water cross over is not integrated with the intake (cooler intake charge), the intake has an "Air gap" for the same purpose, the valves and ports were purpose built for maximal useable lower RPM torque. Velocity at low lifts over Volume at upper RPM's... Seems to me the guys who designed the Nailhead did a fantastic job and used ideas that were cutting edge, if not decades before their time... Edelbrock makes a fair bit of money selling "Air Gap" intakes these days. The things have the torque curve of a diesel... Still intakes that maximize velocity might be the way to go, I would have loved to see how 3 deuces faired in the same Dyno shootout. Or a bunch of Webers... I'm also left wondering how a smaller CFM 4v like a 700 CFM Edelbrock on a fictional high rise (Victor Junior like) manifold would have compared.
Blue printed nailhead+ good port job+ good supercharger+ big carb or efi+ good exhaust system= screamer.
Yes I think that would be the Nailhead, "Holy Grail",and the ONLY way to make what most people today consider, "BIG", Power. Thanks for all your hard work. You have shed some light on my ideas about a build. I'm thinking now that the best bang for the buck (If a Power Adder is used) is to clean up the ports, match the ports, Toms Roller Rockers, new SS Valves, add forged pistons and a great blower cam, then put a STS Turbo on it. Use a "Blow Through" hat and get out of the way. With the boost, I don't think the headers, and the big port jobs will add much of anything compared to the money it cost. Pressurized induction makes a lot of expensive things irrelevant. Oh and a good Tune. Thoughts? Ty
where did you get 4 HP over the single 4 carb, which post? on the thread dyno testing didnt they used the buick 2x4 x manifold and not the b262 or the eelco intake? thanks.
thats not really true.. you cant get air into the engine if you can't get it out. the exhaust is the weakest area on 401/425 heads. porting to get the best airflow possible will help in any engine and is especially important when running boost or Nitrous. there comes a point where the intake charge with fuel starts backing up in the intake manifold because it cant get into the cylinder due to restrictive ports or exhaust not geting out fast enough. at that point it's really simple to blow the intake right off the engine. I'm waist deep in a forced induction 401 project and have been doing heavy research on the subject..i have found i know a whole lot about nothing when it comes to this stuff.:shock:
Maybe I need to re-read the thread, wasn't his baseline run done with a stock 4bbl setup? Never mind, I see now that his first runs were with the 2x4, I shouldn't have assumed he would baseline with a factory 4bbl. my mistake. Erik did you get pulls with the ported 4bbl big carb combo?
Maybe thinking about my experience- a ported/polished matched single carb intake + 750 edelbrock vs the X-code dual quad experimental manifold I threw on there just to see what happened. Not the definative test by any means. That Engine was built to run the single; I will be putting a bit more effort to match up the dual quad to the 425 in my Wildcat. That includes spending much more time with the dual quad tuning than we did on the 401.
Ever try a cam with MORE lift and duration on the intake side than the exhaust? Perhaps about 4-6* more intake duration and .030-.040" lift. Have the exhaust lobe close a bit later to so the piston plays a role besides the scavenging of the spent gasses to get those spent gasses out. This should allow a larger amount of fresh charge into the cylinder and make more power if indeed the intake is the weak side of the nail's head. Seems it is. Just a thought.
Wellllll,,,,, I did not know that I was expected to come up with the "stuff" to prove a theory. I was just offering a suggestion. I stated what would be interesting to me. If I had buckets of money I suppose that I could have pulled the modified manifold and holley 3 bbl off my car and shipped it from Tn. to Or. and let it be tested. Not feasable on retirement pay though. Is there some animosity toward ol Doc????????????
I think Erik's just bustin your horns a little Doc-some friendly ribbin. You know we all love ya you big lug :grin:
It's all good Doc! I was just playing. Believe me, I understand where you are coming from as far as a budget. I would have loved to prove your theory one way or another, too. My pockets(and those that donated to the cause) can only do so much. I was getting a jab in, because you have been making your case about the hogged out single intake with a huge Holley, on many threads for some time now. Closer study of the results might suggest you are on to something... ...But then again there IS all the those "f"ord words you've been throwing around....:grin: let me make it up to you. I'll buy you one----> :beers2: Erik
You know Doc. I'm only here in little ol Crossville. Maybe when I get the little 364 of mine on the mule I'll give you a buzz. Mike
Erik I'm curious why you went with dual quads if you were after torque? Conventional wisdom is that dual quads are for peak hp. single 4 and even single 2bbl carbs should produce more torque in usable street RPM ranges. For torque you want air speed not big volumes. So smaller CFM carbs and dual plane intakes, not giant CFM carbs and tunnel port intakes. if you look at most "high rise" and multi carb intakes for drag racing, they almost all make significantly less torque (10 to 30 foot pounds is not uncommon) from idle to 4000 RPM's than a normal street oriented intake. If you look at Chevy and Ford intakes for big blocks or small blocks where there are loads of dyno data; you will see Intakes like 2x4's Tunnel rams, and even single carb high rise pieces like Edelbrock Victor Jr and Sr. All develop more peak HP than a single carb dual plane manifold. but they move it up into the 4500 to 7000 RPM range, and they make less torque below 4000 to 4500 RPM's (generally speaking). Granted there's not a lot of selection for the nail.
SJ, Everything I have ever heard, or come to know tells me the nail is not like a chevy, and shouldn't be compared to the same way. The nail wants more air which means more CFM. I agree that if we could get shorter intake runners we would see bigger torque numbers. My understanding of how HP is computed (torqe x speed- directly related!) leads me to believe volumetric efficiency VE is the determining factor in the nailhead, hence the small valves.:Smarty: We will likely see proof of this in the very near future when Eelco (any day now) releases their new and improved single 4 manifold for use with BIG carbs. This is only a theory, of course untill someone comes along to do the dyno testing for documented proof. Erik
And I may be doing just that in the very near future. We'll see if it comes to fruition & in time. I would have really liked to send the modified B262 for testing, but as all well know, they are like hen's teeth & if it got lost it would be hard to replace. Then we would have to try & copy the mods that were done. I liked the more even torque & HP graph of the B262 over the Eelco even though the Eelco had just barely higher torque & HP levels. I noticed the Eelco had peaks & valley's throughout the RPM range. But, at least now we have an alternative to the coveted B262 with better sealing improvements for the carbs. Don't get me wrong, I'm not knocking the work, time, effort & expense Marty has gone through. I hope it all turns out excellent for him as well as this new manifold. I, as well as Marty I'm sure, are hoping this new manifold will help our asymatic "Nails" to breath a little better. All in the quest for HP & the famous low end torque the ole "Nail" produces. Tom
Wellll, i am glad yall splained it to me cause I was about to get into my FFFFord and go off and eat worms and die. :Brow: :Brow: :Brow: Now I wonder could I get a big carb to work on that Truck???ray: ray: :laugh: :laugh:
Yeah the "asthymatic" condition has always been the issue with the nailhead. The issue should be to use the motor within the parameters it already has while expanding them as much as possible. No reason to rev to 5300+ if it is not making power, shift 400-500rpm after peak power is the rule of thumb. So work on making power and torque for a longer amount of time(read revs), say from 3000 to that 5300rpm point or whatever each motor has as it's sweet spot. DENSITY is not air but one of the factors that make yup the air with denser air making more power. Maybe a water injection from Snow would be a good addition? I'll look for their site. Keep up the testing!
I would like here more about this Expoxy and Part # and where you can get it.You can PM me as well or call me 720-217-7859 Jeff
