About the D-port heads. I have a virgin pair I picked up years ago from a fellow board member. From the flow results I got without doing anything was the exhaust flowed about 10% less than stock heads. Add clay to the floor to raise it & flow went up 10% above stock. Supposedly they were good for 15HP. If they flow worse how could they gain 15HP??? The intake ports were exactly the same as a stock head. Can get close to 260 flow on the intakes & above 160 on the exhaust with the iron heads. Since the beginning, 1953, everyone thought, because of the long, convoluted exhaust port that it was the exhaust that's the restriction in flow. In actuality in a normally aspirated situation it's the intake because of the "S" turn it has to make to enter the port/valve area. Take & cut off the intake port to get rid of the "S" turn & flow goes up a substantial amount, even over & above a ported head by just eliminating the "S". Under a pressurized condition it now becomes the exhaust that's the problem. I know someone who has two different sets of exhaust manifolds for the D-port heads & know of one other who has one set of manifolds. The main difference between the D-ports & stock heads is that the exhaust outlet is bigger by about 1/2". On a set of my friend's heads, welded up the outlets & they flow the best yet, & get this, the outlet size is even smaller than stock. It appears the exhaust goes up, hits the roof, curls around & ONLY comes out in the lower corner of the port. So much for bigger is better. On the exhaust port, when the D-ports were made around '61 or '62, in the quest to make the port larger not only did they drop the floor but also raised the roof. Too bad they didn't just raise the roof. I'm sure that would have made the difference. Chrysler did the same on their "W" heads around '69 or '70 & found that was a BIG mistake. Buick was WAY ahead of Chrysler by about 8 or 9 years. I know that just raising the roof on a stock iron head the flow will go up a fair amount. It's getting late & 5am gets earlier & earlier the older I get. So goodnight for now & MORE to think about. Tom T.
I would be interested in a set. About seven years ago I was working on doing some extensive modification to the exhaust port of a pair of nailhead heads. My thoughts at the time were that the spark plug recess put a nasty right angle bend into the exhaust port coming right off the bowl. I made a steel sleeve which I brazed in place to bush it down to a 10mm thread spark plug with a 9/16 hex. I was able to open up that bend almost .200, later I cut that head apart and found it cracked out on me during the brazing. If you are casting fresh aluminum that is not a problem. On that same set of heads I was working on installing 2.11x1.71 Pontiac valves as well (It is possible with a .187 offset). Stock heads are too thin to open up, you will cut into the side of the chamber trying to cut a seat this large and it would be impossible to open up the bowls enough to make those huge valves work. But again with a fresh casting the sky is the limit. While you were at it cast a rocker arm with an offset pushrod cup rather then using an offset roller lifter. People turn their nose up at the intake flow of a nailhead but the Chevy guys aren't getting much more then 245-250cfm out of an all out ported 1.94 valve head. Eliminating the water jacket over the intake port roof and redesigning the floor in conjunction with a larger valve might just do the trick ( and keep a stock style intake to boot). Please keep me informed. Very much interested in a pair of aluminum heads, they would look great polished attached to my boat.
Well, for one member, YES, GBE IS ME! As far as the heads, I was thinking ALL friggin night long, in my sleep, awake and more thinking about these heads. First of all, my heads may not have to be cut lengthwise as I have a few guys coming to pick up my stock head for a 3D graphic image of the interior such as ports, water jackets and the like. Then the head will be put on software and a 3d image produced that I can play with. The valve guides (press in's) will be kept in the heads so these will be a permanent fixture so the bronze guides installed. I was going to eliminate the soft plugs near the spark plugs since I never see the heads break, its usually the side of the block. And if you have freeze plugs popping out of your motor, then you don't take care of it. (lack of antifreeze) That is why I run Evans Coolant. It doesn't freeze... stays like a slurry. The heads will be milled down a little to bump up the compression, and I might do something about the bowl configuration.... I have alot of ideas, I just need to get the ball rolling... The donor head will be disassembled tomorrow. Then hot tanked, sand blasted, and all the casting flaws and numbers will be gone. The software we have will take into consideration that the exhaust port is lets say 1 1/2" x 1"..... and with a few key strokes, we can bump up the interior size by 1/4" through out the tube length. So instead of just getting a head and playing with it, we will be manipulating it through software first. Then a casting can be made from that easily. Kind of star wars kinda stuff.... My idea of work smarter not harder plays into this. Please keep all the great ideas coming around! Maybe the exhaust valve needs to be smaller and a larger runner implemented so it creates a venturi effect??? Who knows... its fun to play right now with the idea and go from there.... I also have my nephew who is an aerospace engineer that can do the math for me too...... 1+1 is 7, right???? I like the idea of multiple valves in the head, kind of like honda in the 80's, they had a 3 valved head.... but if I REALLY had the money, I would create my valveless head I designed in high school. (no cam/lifters/valves/pushrods or any other parts like these. Would save alot of $$, but would have to be 100% created from new.... and I dont have that kind of money....
Its been a long time since I took a good look at a nail head. Its better to get max flow with bigger heads a different combustion chamber and relocation of spark plug. If you are going to do all that you might as well adapt a 455 head. I am finding out that almost anything can be done but you will need an intake and new headers. We have just upgraded our design plans on a 350 to get 325cfm+ but will be a little while to see what we get on exhaust. We are doing these to bolt on a standard bore 350. If you are spending the money you might as well do it right. Hope you can find about 100 buyers to make it pay for itself. Everybody quotes low prices to reel you in then we know what happens next. I paid over 4000 bucks and never got the bulldog block! I could get a head from JESUPERCAT if he has one laying around to look at. Don't be offended but I won't be using my money to make one. The 350 and 455 head are first. I wish they had a good head for a 401-425 the block is stronger than a 455 but they are getting real hard to find them. Good luck!
From my and friend's point of understanding the exhaust port behaviour (generic), if intake flows on the bottom - due to vacuum, the exhaust flows on the top! Because that's the vector of gases, where it's being pushed. So it literally slides on the top of the exhaust port, i.e. longer curve. I believe that unchoked crossover passage actually helps exhaust performance below 4000 RPM. (by choking I mean steel intake gasket with small holes) Because gases from the one head literally push the exhaust gases on the other, and so under sum of vectoral force they are meant to target towards the exhaust manifold side. I believe, that's the idea of things, not sure it works like a charm in real life conditions. Regarding the intake, yes, the S-curve is not good for performance. The reason for is the horizontal intake flange design. It could benefit a lot more from, say, a 45 degree intake manifold flange angle that would help getting rid of the first part of the S-curve. If you're going 3D, you can use 3D printer for prototyping the ports. They can print thin wall stuff, which would be fast and cheap. A thicker one can be even flowed on the bench, I think. Some pictures from some late soviet books, for your interest. There are far from performance use, but help to understand things better. The illustrations show huge diesels, actually. Intake port flow left - 4 mm lift, right - 16 mm (great valve seat design, I know, haha) Exhaust port flow Left - hot air flow, right - exhaust port flow again Some more exhaust flow
Hey Ken,I don't know how familar you are with a Nail Head engines,but do to the angle of the lifters it may not be possible to run a 455 style head on a Nail. The push rods actually are routed to the outside of the head and acuate the valves from the oppisite side as a 455 style head. Back in the day they did this so the engine would be narrower than a convetional valve setup to fit easier between the frame rails.:shock: And the Nail Head has the number 1 cylinder on the passenger side front cylinder,making that side the forward bank,so a whole different intake would be needed also.(or a custum sheet metal intake)No way to make a 455 intake work on a Nail Head engine. But your right about the block,plus they don't have the oiling issues that the 455 blocks have. Plus I think the factory cranks are forged instead of cast,so a bunch of welding on them can give them more stroke.:Brow: Or even the use of a BB Chrysler forging that can be made to fit in a Nail.(won't work for a bbb 455 because the mains aren't forged big enough to get 3.25". I am surprised that no one with an aftermarket bbb 455 block made with 2.75" mains hasn't tried using a bb Chrysler after market forging though)o No: Derek
The "Nail" crank can be used in a BBB 455block. They are made of a 1030 forging. No need to weld up a crank for stroking. I know it was done many times in the past, but my thinking, putting that much heat in a crank will cause it to warp. Sure you could straighten it, but once put into use through the heating & cooling cycles it will oft times go back to being non straight. Besides you lose the fillets for strength. Offset grind & can gain up to 3/4" stroke. Problem is there is NO amount of porting that will satisfy the needs of the added cubes, nevertheless 400 or 425. As it is a max ported set of "Nail" heads can only support around 320 or so cubes. ALL engines are just air pumps. We sometimes forget how an engine makes power. It's ALL about the AIR!!! Air = RPM's, RPM's create HP!!!!
I hear ya,but if the Nail Head engines get good flowing aluminum heads what I mentioned could be a reality,and thats why it was mentioned. With the factory head flow now,it is pointless to increase CID. The only gains from more CID with a Nail Head is torque with less RPM capability,with only minor HP gains. I have NEVER heard of anyone using a Nail Head crank in a 455,although spacers could be made to make it fit,I don't think it would be a good idea. The reason for the 3.25" mains in a 455 is to stabilize the light casting of the block to control harmonics,and using 2.500" mains in that block wouldn't be a good idea without a full girdle. But the short block of a Nail Head is screaming to be spun with its 2.500" mains and its slow bearing speeds and forged crank and good oiling. Buick dropped the ball on the heads all those years ago though,and just settled for the torque to make the engine that fits better in between narrow frame rails. And like I said,a BB Chrysler after market raw forging can be machined to fit in a Nail Head,so all that welding and offset grinding wouldn't be necessary(it has never been done before because of the lack of head flow). What would be necessary would be heads that can flow enough air to support the added CID. This thread is about after market aluminum heads after all,and aren't the heads "ALL about the AIR!!! Air = RPM's, RPM's create HP!!!!" = good flowing heads so all this can be done to a Nail? Derek
When I worked at Kenne-Bell back in the 70's Jim had a 455 with a nail head crank in it about 397"'s for a circle track motor that we never used. IT was since sold and I have no idea what happened to it. I did run nailheads in the early 70's both 401's and 425's. For some reason the cast pistons didn't like over 7000rpm and the motor went......kaboom! If I made a head I would change the valley cover and make the head wider into the valley area to change the way the pushrods work. It would take a lot of money either way. New rockers etc. etc. This is why no one has done it. Our 455 head flows 447cfm now, it is a TA S2 solid casting for alcohol or nitro. We might get a couple more cfm but I just want to run the head NOW! Best bet is to take a head to a CNC digitizer then change the program to add more meat where you want. When you are done have it cast with water jackets. There must be a Buick guy who can do this at work?????????? Well it sounds cheap and easy.
Bob Makely at Finishline runs a "Nail" crank in his 455 with a blower. He didn't want to spend the BIG BUCKS for a Moldex crank & wanted to spin the engine to 8K. He has done this & as far as I know has been doing it for the last few years with no problems, again, as far as I know. The main bearing speed with a 2.50" main is good. The rods journals are another story at 2.25". That's why offset grinding is an advantage. You can get a smaller diameter bearing for less speed & not disturb the fillets for the strength, especially, with a 2.100" diameter you can now get ANY bearing you may want or need. Many crank grinders have told me that a "Nail" crank can be cut down to Honda size (1.88") & still be stronger than many cranks out there today. This of course DOESN'T include special/custom cranks. And, don't forget, the frame rails that held a straight 8 many years ago was some very EXPENSIVE real estate at the time. Of course, the reason for the design. Even given these bad points they do & I have PROVEN they CAN RUN even with the restricted breathing capabilities.
A "Nail" crank in a factory 455 block or an aftermarket 455 block? And I'm sure if its a factory 455 block he is running a full girdle,he likes to go fast!:eek2: I wonder what he did for the mains,an aftermarket block can be ordered with the main size of choice,but with a factory 455 block some sort of bearing spacers or main welding would be needed.uzzled: And yes a Nail Head is screaming for some heads that can flow some air so the bottom end can run at its potenial! I would love to see this venture a total success,with aluminum heads that flow 300+ cfm on the in. and 200+ cfm on the ex. would be SWEET!:Brow: Yes the Nail Head engines have proven themselves in the history of hot rodding,its about time they got some after market support though,to be able to spin that low end that is just waiting for some RPM to make torque and HP.:TU: Derek
This will be the time to straighten out the runners as best you can and still use stock intake exh. manifolds. The way the air enters the intake runner has a ramming affect. It can handle slightly higher velocity over the short turn because of the verticle runner. I have slowed down the short turn from over 400 fps to around 350 to 370 fps and with the right shape the turbulence goes almost complety away and of course cfm goes up. Starting with a freash mold you could really fix it up right. Same with the exh.. , a few things you could do. I will say it again , Good luck mr62...Should be fun to watch as this goes on
Also I doubt it'd be possible to use bronze guides successfully on the nailhead with a big lift cam, due to giant loads from short length rocker arms. So cast iron guides are the best shot. It's possible to use beryllium copper valve guides, but I think that only a higher content of beryllium than common 2% would work with the factory valvetrain configuration. Since beryllium gases and dust are hazardous for breathing, that kind of BeCu guides are hard to get and might be expensive or even illegal in the US. p.s. Personally, I don't like BeCu valve guides. The heat conductivity falls with the increasing amount of Be content, so a 2% Be valve guides have something in between 50% and 70% of normal bronze conductivity. Maybe some of the bronze offered by Moldstar might work. Also powdered valve guides might be the best of both worlds, like the material used on Chevy LS valve seats.
Bob, do the stock intakes flow well enough to support better flowing heads? Perhaps taking another look at the heads' modified intake flange should be considered at this point. It would require a new intake manifold. More details of that head mod here: http://www.v8buick.com/showthread.php?161474 Some other considerations: -Raising the exhaust port would be nice, but changing that significantly would require different brackets for alternator, power steering and a/c. I'd guess most buyers wouldn't mind having to buy new headers for an improved head. -Moving the valve guides apart to fit larger valves... how far can we go while still using the stock rockers? -As mentioned, using smaller spark plugs would give more room for mods. I need to take a look at that. - Want to incorporate fuel injectors?
I don't know about the load on short length rockers, but I do know something about machining beryllium. I worked at a high tech shop in 1971 and we had a girl in the burr shop die from beryllium poisoning. She had worked there for years. No one else had a problem and within a couple weeks ever mill lathe and drill press that had anything to do had a special vacuum system connected so ALL the dust was sucked away. Just a few years ago I had the beryllium copper seats put in a set of S4 heads. No one will ever have to worry about handling them or the seats. I would not lick the seats but I would not lick the titanium valves either. The EPA will outlaw bananas someday because some people's mouth itch when they eat them.
Yes but at the beginning of the thread he stated he had everything in place to move this along swiftly.
If they produce better flow, look nice and have the hp and tq numbers to prove it, i wouldn't think twice about dropping $2500. This would be like a dream come true for me, lighter car, more flow, more tq, more hp N/A and support better flow for nitrous. I dont wont to turbo or supercharge, i love keeping everything simple. Good heads, good valve train, light rotating mass, big carb and msd ignition and maybe spray.
