porting can help

Discussion in 'Cams, Heads and Valve Trains' started by grumpyvette, Oct 10, 2008.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    small block

    big block


    its generally a very good idea to keep all the cam, lifter,valve train and cylinder head components in matched sets, keep components in labeled matched sets, if you intend to reuse used parts in a rebuild. as each wears in, or laps in to its matched components a bit differently thus random assembly increases the chances of future parts







    http://www.youtube.com/watch?v=-IljMBoV ... cqomISHZOE




    http://autospeed.com.au/cms/title_Porti ... ticle.html



    http://www.harborfreight.com/cpi/ctaf/d ... mber=99698



    this model die grinder is surprisingly good quality for a disposable throw away die grinder,and usually last for more than two cylinder heads, its a true bargain, if it lasts only for two! don,t even think about use of the hard stone grinding bits they shatter and are cheap crap, get real carbide burrs

    btw it helps a great deal to dip the burr in a shot glass of WD.40 about every 20-30 seconds as it helps keep it from picking up crud sticking to the burrs cutting edges,the little bars of soap from the hotel bathrooms or beeswax, can be used as those melt, because the burrs heat up and as a result the melted bits get thrown over the surfaces
    Speeds & Feeds for Carbide Burrs
    Carbide burrs should typically be run at
    1,500 - 3,000 Surface Feet Per Minute (SFPM)

    SFPM = (RPM) (3.14) (DIAMETER) divided by 12

    RPM = (SFPM) (12) divided by (3.14) (DIAMETER)

    The following are general speed recommendations and may need to be adjusted to your specific application.

    Carbide burrs and carbide rotary files, like high speed steel burrs and rotary files, are safest when used with the shank all the way into the collet and only the head is exposed.

    Extreme care should be exercised when the head of the burr extends farther out. Too much pressure or too much speed might cause the shank to vibrate or bend while the burr is spinning, or teeth to break.

    Carbide burrs up to 1/8" (3mm) diameter may be run at speeds up to 75,000 RPM, depending on the material being cut and amount of shank exposed. Go slower if the shank is exposed.

    Extra long carbide burrs should be run 25% slower than a standard burr

    Carbide burrs ranging in size from 3/16" (4.75mm) diameter to 3/8" (9.5mm) diameter, a 30,000 RPM die grinder is recommended.

    Carbide burrs ranging in size from 1/4" (6.3mm) diameter to 1/2" (12.5mm) diameter can usually be run effectively with a 22,000 RPM die grinder.

    1/8" (3mm) diameter: 45,000 - 90,000 RPM
    1/4" (6mm) diameter: 23,000 - 45,000 RPM
    1/4” (6mm) x 6” long: 17,000 – 33,000 RPM
    3/8" (10mm) diameter: 15,000 - 30,000 RPM
    1/2" (12mm) diameter: 11,000 - 22,000 RPM
    3/4" (20mm) diameter: 7,500 - 15,000 RPM
    1" (25mm) diameter: 5,500 - 10,000 RPM

    If the shank is exposed, slow it down

    Carbide burrs, like all cutting tools, are dangerous. Use caution when using any cutting tool, and always wear appropriate eye protection and safety equipment. Never exceed the manufacturer's recommended speeds and feeds for any cutting tools.

    Never, ever, grab a spinning burr. Let the burr come to a complete stop before touching it. The fingers you save may be your own.




    Stage 4 Melanoma Therapy
    A Treatment for
    Metastatic Melanoma.

    http://www.mcsdepot.com/browseproducts/ ... REACH.HTML

    be sure you order the correct matched shank diam. burrs

    If your trying to match the carbs throttle bore or venturie base size to the carb spacer you intend to use you want a smooth transition, from the carb to the intake plenum, I generally start with a carb gasket matching your intended carb to be used!
    measure its secondary size accurately
    place the spacer in a vise on the mill, or drill press, accurately index the hole saw

    line up the carb ,mounting bolt holes, spray the spacer with bright red paint and use a properly sized hole saw ,on a mill or drill press to open the rear section venturies and a die grinder to contour the remainder

    related info

    http://www.popularhotrodding.com/engine ... ewall.html

    http://www.popularhotrodding.com/engine ... ewall.html


    http://www.enginebuildermag.com/article ... power.aspx

    http://www.hotrod.com/techarticles/engi ... ewall.html
    Last edited by a moderator: Oct 23, 2017
  2. grumpyvette

    grumpyvette Administrator Staff Member

  3. 87vette81big

    87vette81big Guest

    I found your own Ancidotes most interesting Grumpy.
    And by RCS CNC Cylinder head porting.
    Concurrs with what I know about Select Casting number Pontiac Iron heads.
    On the street Accelerating HP More important.
    I allways calletd it High Speed Torque.
    Pontiac V8 & BBC Seem to do it Best.
    Olds V8 is decent but lacks modern refinement .

    Something no engine Dyno or Chassis dyno can measure accurate.
    Only 1/4 mile race & street racing action.

    Something unique about the Pontiac V8 Intake port shape still.
    Dictates much of the engines personality.
    Talking normally aspirated Action.
    Boost changes much.

    The 71 GTO #66 heads are decent for my needs.
    Minor cleanup work. Gasket match.
    Spend most of my time on the Valvejob.
    3 angle seats. Maybe 5 angle.
    No core shift on the iron heads like many aftermarket aluminum.
  4. 87vette81big

    87vette81big Guest

    I know I shouldn't laugh but all with AFR 195's are going to get thier Dicks Blown off Street Racing The Hellcat.
    The Greatest Fucking Scam in the Corvette World Ever.
    The Truth does Prevail Grumpy.

    I stand A Decent chance .
    Poncho 455 Power.
    The Fuck if I will use AFR.
  5. grumpyvette

    grumpyvette Administrator Staff Member

    Last edited by a moderator: Oct 5, 2017
  6. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    watch the video, and like I stated many times,
    its the combo of the engines,
    displacement ,
    cam timing
    and the exhaust scavenging ,
    and the intake manifold design,
    NOT the intake port cross sectional area,
    that are the most critical factors, in the engines lower rpm and mid rpm torque.
    but for damn sure an intake runner port can be small enough to noticeably restrict upper mid range and peak power significantly,
    For 5 decades I've heard endlessly about how installing larger free flowing cylinder heads would devastate the engines ability to make any low or mid rpm torque.
    especially when Id suggest using a set of smaller 300cc-320cc, aluminum,rectangle port heads on a 496 BBC, or 200 cc-210cc heads on a 406 sbc, I was asked to build
    yet on every engine I've ever had built or had some guy ask me to look at, to see why it ran a great deal less impressively than he expected it too,
    they brought into my shop its was very obvious (at least to me) that it was the combo of low compression, too little displacement, with too much cam duration ,
    a restrictive exhaust or some guy who was trying to save money and continuing to use a stock stall speed torque converter, or retain a badly mis-matched 2.87:1-3.08:1 rear gear ratio,
    with an engine that he miss matched components by slapping a large carburetor , and a single plane intake on,an engine that will rarely exceed 6000 rpm, that was the major reason.
    if you want an engine combo to run your first step is to logically match the list of components you,ll use to the application,
    and that requires you stop, engage the brain and think things through carefully,
    and the most common way to screw up the process is to over cam a low compression engine,
    have a restrictive exhaust or mis-match the drive train gearing to the engines power band.

    don,t be too concerned with getting a mirror like polish on your intake ports runner surface finish
    a slightly roughened but consistent surface can be beneficial in reducing the tendency for fuel droplets to sheet or fall out of the air stream thats pushing or dragging the air flow into the cylinders

    back in the late 1960s to the 1980s every set of professionally ported cylinder heads I ever bought or saw had a mirror like surface finish, this was expected by customers and I know guys that sent back heads with less than a perfect port wall mirror finish.
    as scientific testing got more accurate it was found that leaving the small surface, machine tool marks on the surface of the ports cause a boundary layer of turbulent air that tended to allow the AVERAGE TOTAL air flow through the port to increase and maintain a better fuel/air distribution ratio
    ports like this were common

    lately some porters have begun to machine micro divits on port walls to duplicate the golf ball like surface , but thats not necessarily required or beneficial in relation to the extremely time intensive and EXPENSIVE AS A RESULT machine work is not going to provide huge gains.
    polishing the combustion chamber surface and smoothing out sharp edges and contours to help UN-shroud valves, and removing sharp edges in the spark plug threads that enter the combustion chamber that can aggravate carbon build-up and provide ignition hot spots for detonation, is still a proven and beneficial practice


    I was recently asked about why anyone would pay a great deal of money,
    to buy high flow aftermarket cylinder heads and then,
    it seems totally wrong too start grabbing a grinder or dremel tool,
    to start modifying what should already be a far more precisely made cylinder head.
    well there's literally thousands of potential parts combinations ,
    and theres no way, that you can almost randomly mix and match,
    even the best brand name components and maximize the flow rates,
    without taking the time to customize the fit of those parts together.















    Last edited: Aug 14, 2018
  7. 87vette81big

    87vette81big Guest

    That's an amazing job Dimpling the Intake Port Grumpy.
    Had to been done by a CNC Program Mill.
    If by hand the Guy is an Artist .
  8. 87vette81big

    87vette81big Guest

    I see Berlenium copper seats.
    Full Race meant to be used with Titanium valves.
  9. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member



    On the surface, flow bench testing seems easy, but it’s not. Many in the industry have become solely fixated on cubic feet per minute (cfm) numbers, placing importance on a number that is easily manipulated and ignoring other data about a cylinder head’s performance. This thinking would make flow bench testing seem easy, but this thinking is wrong and won’t do you any favors come race day.
    Here is a deeper look into flow bench testing and what you really need to know to have the right cylinder head and induction system set up for your engine.

    Experienced cylinder head designers and head porters often tell people not to pay attention to flow numbers, but that does not mean that flow numbers don’t matter. This distinction is often lost in translation. Flow numbers are important, and they do have meaning. Just not the meaning most people attribute. Airflow numbers give insight into the potential for power. However, they don’t guarantee you will make more power.

    “What professionals in the industry really mean to say is flow numbers alone don’t matter and cannot be used to judge the power potential of a particular cylinder head design,” says Darin Morgan, manager of the cylinder head department at Reher Morrison Racing Engines. “Flow numbers are just one variable used for various equations to analyze port characteristics in a very complex system. You can have 10 different ports with the same exact flow numbers, yet they can vary wildly in RPM range, acceleration and power.”

    The complexity of cylinder head set up and flow bench testing comes in the form of math, aerodynamics, thermodynamics and the physics it takes to design the correct port and manifold design for a particular engine combination. These processes take years to master.

    By the Numbers

    Cylinder heads often can be close to one another volume-wise, but they can vary drastically in flow curve. People mistakenly believe that if they buy a cylinder head that flows more air and has a big CFM number, they’re going to make more power. It’s really easy to get flow numbers – just make everything big and put it on a big bore and you’re done. However, the testing data will be useless to an engine builder without knowing all the other variables you need to know.

    The factors that determine the performance of a cylinder head are complex. A head that is ported without considering air speed, the size of the engine, the rpm range, the location of the valves, and a dozen other parameters isn’t going to be the best head, regardless of its peak airflow.

    There are many questions that are much more important than airflow: How far are the valve heads off the cylinder wall? What’s the ratio of valve size to bore diameter? What’s the ratio of the airflow to the size of the valve? What’s the size of the port, what’s its taper, how high is the short-side radius? The answers to these aren’t as simple as comparing a flow number, but they are what really make a difference in an engine.

    “When I flow test a cylinder head, the CFM number is the last thing I look at,” Morgan says. “The flow bench tells me air speed, and there are really three rules to making horsepower – air speed, air speed, air speed. We design a port that has to flow X amount of air, but it also has to have X amount of average velocity, X amount of peak velocity, and you have to tune the runner harmonically on the system and on the bench itself. If you design the port properly, it will automatically flow a lot of air.”

    Valve and seat configuration is the most important area in the whole induction system because it controls the air entering the cylinder.

    “We want to make that area as efficient as possible,” he says. “Flowing the most air is easy, but it won’t have any air speed. So there is a give and take there and a balance that has to be struck between the mean air speed, peak air speed and air flow. Without all that information, an engine builder can’t make a reasonable decision. People go shopping for CFM numbers because they don’t know all the underlying things that go into it.”

    So you’ve put a cylinder head on a flow bench and you have a bunch of numbers. What do those mean? Morgan looks at the discharge coefficient.

    “The discharge coefficient is using the area available to me at maximum efficiency,” he says. “If you don’t have a high discharge coefficient, you can’t pull fuel, you can’t move air through the engine and it won’t accelerate. Secondly, average air speed in the system has to fall in the 246-268 feet per second range. The peak velocity should not exceed, depending on piston speed and other factors, between 285-310 feet per second at the tightest area in the port. Two-valve, push-rod engines have a pinch point and no matter how we avoid it, we always end up with a slight pinch point. That pinch point’s air speed should never exceed 300, and if you do that, you know you’re safe.”

    What you have to keep in mind is bigger ports don’t necessarily make more top-end power. The right size port makes the most top-end power.


    Understand Your End Goal

    The cylinder head designer and flow bench tester need to know your end goal. With a couple of measurements of the cylinder head, an experienced veteran like Darin Morgancan tell you whether it will hit its target or not. If the measurements are in line and it’s a good cylinder head for the combination you want, it can be put it on the flow bench to see if it has the flow potential to do what you want to do.

    “There’s a million ways to get 420 cfm, and there’s only one right way,” Morgan says. “Every single cylinder head is engine specific. The engine’s intended use is very specific to the induction system design. Two engines that make the same exact power at the same RPM will have different induction system designs whether they are a jet boat engine, truck and tractor pull engine or a drag engine. The engines will have different cylinder heads on them because they operate dynamically different.”

    A jet boat goes up against an RPM and holds there. A truck and tractor pull engine will hang the RPMs at 9,600 and then draw them back to 9,000. A drag engine has to accelerate through the gears.

    “All three have completely different intended uses, so runner links, port sizes, valves sizes, and chamber dynamics will all be different,” he says.

    Drag Engine: A drag race engine or an engine that has to accelerate through multiple gears is very, very sensitive to change and requires a finite combination. “You’re either on with your air speeds, camshaft and manifold or it’s off,” Morgan says. “We put the air speeds as fast as we can get them with the discharge coefficient as high as we can get it so that it’s on the edge of nosing over or going too fast. At that point it would spike at the fuel curve. It would use more fuel at the top of the engine’s gear change and help it reaccelerate at the bottom.”

    Truck pull engine: Because this engine gets wound up, it doesn’t have to accelerate up through the power band. Drivers take it right to 9,200 RPM and then it slowly climbs and doesn’t have to use a lot of energy to accelerate the internal components. “You can make the ports a little slower (10 feet per second slower). This change will help it make more power,” he says.

    Jet boat engine: Again, using the same engine, let’s say its maximum efficiency is 8,500 RPM at the pump. “We would cam it and shrink the ports back down to where the air speed is about 20 percent below critical max for choke, right where the pump is most efficient so I can get the most air speed and most cylinder fill right there,” he says. “Then I would harmonically tune the induction system to be tuned at exactly that point.”

    The cylinder head needs to have a flow that is reasonably compatible with the expectations of its use. For all three of the above combinations you’d have different sized ports, different length runners, different manifolding, and different camshafts.

    Common Pitfalls

    Again, flow bench testing and focusing on just CFM seem easy, but that’s where people make what amounts to wrong decisions. There are numerous pitfalls you need to watch out for.

    “The first pitfall I see is not flowing on the bore size that’s going to be used on the engine,” Morgan says. “I see this problem industry wide. If you flow a cylinder head on a 4.600˝ bore and put it on a 4.500˝ bore engine, it can kill 50 hp because it leaves a ridge all the way around. People buy heads that were designed for a 4.600˝ bore that flow 420 CFM and put them on a 4.500˝ bore and they end up flowing 390 CFM. The problem occurs because that valve size and that port is designed to flow X-amount in order to get the air speed in a certain range. So now you’ve not only killed the airflow, but you’ve killed the air speed and completely destroyed the dynamics of the cylinder head.”

    Another pitfall of flow bench testing is not flowing with the valves you’re going to be putting in the engine. The whole testing regiment has to mimic the engine or the data is useless.

    “This is why if you shop cfm numbers you will lose,” Morgan says. “CFM is one of only 50 variables that matter, but it is the only one the general public knows to pay attention to. Those other 49 variables matter to be able to design an induction system and properly match it to an engine combination.”

    A third pitfall is not calibrating your flow bench. Calibrating a flow bench is as easy as getting on the phone and ordering a scientific calibration plate. Despite this ease, the majority of flow benches have never been calibrated and it throws data way off.

    Testing leakage is also an important step to remember. Every set up, no matter how good, you might have a small leak here or there.

    “Sometimes it might only be 2 CFM, which is statistically insignificant,” he says. “Sometimes it’s 5 or 8 CFM, but you need to quantify that prior to your flow test so you can take that into account. This is only an issue to the head designer, because my data has to be dead set accurate or otherwise all my other equations are in error.”


    Airflow isn’t everything. We know that there is a finite limit to how long the valves can be open before performance suffers. That is because the valve events have to be in harmony with the rest of the engine.

    The same principle applies to cylinder heads. Simple airflow capacity should never be the first consideration in evaluating cylinder heads. Characteristics that are far more important include air speed, port cross-section, port volume and shape, and the relationship between the size of the throat and the valve seat. If these attributes are wrong, you can work forever on the flow bench and not overcome the fundamental flaws. So the next time you’re considering a cylinder head or reading the data from a flow bench test, make sure you understand all the necessary data for your engine and application. ν
    Last edited: Mar 22, 2018
  10. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    one issue I see is the constant mental disconnect between the guys intended use when someone buys cylinder heads based on the posted flow numbers, and reality,
    posted flow numbers and performance that results will vary significantly when you mis-match components especially when guys fail to realize the engine they are building has very few of the same components or dimensions matching the posted
    “I see this problem constantly. If you read in the advertising that a certain cylinder head flows 300 cfm, on a SBC engine , very few people ask at what valve lift and what bore size and then, ask themselves if the engine they build will have much or anything in common. , if they used a 4.155 bore size to test the heads and your bore is less, like a 4.060 the resulting valve shrouding it can kill 30-50 hp because it leaves a ridge all the way around, the combustion chamber that was not there during the advertised flow test. People buy heads that were designed and tested on larger bore sizes or advertised in dyno test articles when an engine used a cam with much higher compression and a much more radical cam with a tighter LSA and more duration, and are stunned and disappointed to find they don,t get similar results using much less duration, lift and compression on a smaller displacement engine! The problem occurs because that valve size and cam lift and duration,must match the intended application, and that port is designed to flow X-amount in order to get the air speed in a certain range. So if your particular engines component list is nowhere close to the magazine articles configuration, you’ve not only killed the potential airflow, but you’ve killed the air speed and completely destroyed the advertised flow dynamics of the cylinder head you based the cylinder heads purchase on ,expecting the heads to flow as advertised.”
    this works at both extremes, I see guys buy cylinder heads with much to small/restrictive ports who are convinced that a larger head will kill all the low rpm torque, only to find the heads strangle the upper rpm power,and guys that over cam an engine with too low of displacement and compression, and who fail to install effective headers and a low restriction exhaust behind the headers, who then erroneously blame the cylinder head port size for the lack of power that results.

    Last edited: Jan 19, 2017
  11. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    Cylinder head, intake or exhaust port volume is measured with a burret and some colored liquid the same way that combustion chamber volume is measured ,
    the intake gasket surface must be flat level and facing vertically and the valve must seal and hold the liquid from leaking
    read through these thread's and look at the posted pictures





    Last edited: Jan 27, 2017
  12. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    Id like to point out that if your going to port match or port heads , take the time and effort to buy and USE some safety equipment like a face shield, clear glasses and use a decent vacuum cleaner to limit flying trash, I recently had a guy I know spend several hours in the local hospital with an optical surgeon who removed an aluminum splinter from a guys eye because he was porting a set of heads without any safety equipment, that bit of lack of sense cost over $4300 , so spending less than $150 on everything you might need to do that job and dozens of similar jobs makes a great deal of economic sense and it can avoid a great deal of pain and might save your eye sight





    a decent cylinder head stand helps

    http://www.harborfreight.com/air-die-gr ... 99698.html
    btw theres a strong tendency for guys who are new to porting work to bear down or apply significant pressure on the burr and thats going to both burn out the burr , rapidly increase wear on both the burr and die grinder, and tend to cause mistakes in profiling the port walls
    its far better to simply let the burr flutes nibble away at the areas that need clearing and frequently dip the flutes in a cup of WD40 to prevent the flutes from filing with debris and cooling them.




    btw it helps a great deal to dip the burr in a shot glass of WD.40 about every 20-30 seconds as it helps keep it from picking up crud sticking to the burrs cutting edges

    http://www.harborfreight.com/air-die-gr ... 99698.html
    I usually buy these three at a time, they last a long time but think of them as disposable like the BURRS because they do wear out and at roughly $20 each are a bargain even if you need to occasionally pitch one in the dumpster
    you can order this set of these long carbide burrs for about $36-$40


    http://www.mcsdepot.com/browseproducts/ ... REACH.HTML
    http://www.browntool.com/Default.aspx?t ... ductNumber

    http://www.grainger.com/category/carbid ... alog/N-9o0

    http://www.eastwood.com/8pc-dual-cut-ca ... shank.html

    http://www.victornet.com/subdepartments ... /2150.html






    most of the time you'll find a few seconds time to put on safety equipment and the minimal cost spent is far FAR less than it costs in time and money to deal with the medical cost resulting from rushing into a job without their use!Ive generally used and strongly suggest you consider using, one or both of these when using angle grinders or while porting heads due to learning from past experiences
    http://www.homedepot.com/p/DEWALT-Safet ... 220499-_-N

    http://www.harborfreight.com/adjustable ... 46526.html
    read these threads






    Last edited: Mar 15, 2018
  13. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    yeah I know a few of you would rather gargle broken glass scrap than read links and sub-links but trust me if I tell you in the long term, youll gain a wealth of info you need to use to build an exceptional and durable engine, the secret is mostly in getting each component working to its maximum efficiency and in maximizing durability, you won,t win many races or enjoy owning the car if it spends most of its life being repaired or waiting for replacement components to arive, and in many cases simply thinking things through, and selecting the best quality matched components you can afford, and carefully installing them with the correct clearances and lubrication and cooling goes a long way to reaching that goal.
    if you, as the engine builder, have a choice.
    ID suggest you always give up that 5% in peak power potential,you might get by running on the ragged edge , if you can gain 10%-20% increased durability, by not pushing things to just at the point the parts are likely to fail, and knowing that point takes either experience or knowledge gained by watching others fail. and in many cases thats an option if you fully understand exactly how and why things are intended to function.
    porting that intake port wall paper thin , pushing the rpm's you your constantly bouncing the valve train into valve float, or not having consistent oil flow on the critical components might seem like a route to gain an edge in power needed to win races, its much more likely to see you drain your checking account trying to do expensive repair work when components get pushed to the point of catastrophic failure





    Last edited: Jul 9, 2018
  14. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member





    a great many guys are rather reluctant to even attempt to do minor port , runner and under the seated valve,and bowl area in the cylinder heads.
    now I can readily see the reluctance to screw up a set of $1000-$4000 cylinder heads if your un-familiar with porting,
    and I would certainly not try screwing with very expensive heads, but theres a great deal of potential in flow to be gained percentage wise,
    with the cheaper or stock heads and very little chance, of screwing them up, if you stick to mild port matching and bowl clean-up work.
    theres several videos posted earlier in the thread, a good amount of related info is presented.
    Ive found that use of a shop vacuum sucking prodigious air flow from the other end of any port you work on and good strong lighting are very helpful.
    as previously stated, your prep for the job helps improve results, don,t get carried away or overly concerned, , minor casting irregularities,
    and port matching extended as deeply as you can, easily reach can provide measurable boosts in air flow with almost no chance of screwing up the cylinder heads.


    a decent cylinder head stand helps

    Last edited: Apr 12, 2019
  15. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    One of the Pros Porters on FB had a Valveseat come out on a customer.
    Factory installed.
    Not his fault.
    Aluminum Cleveland Race.

    Spotted another on a Pontiac No Prep drag race group.
    Water shooting into the combustion chamber.
    Kaufmann D-Port heads on a drag engine.
    Porosity issue or Valveguide goes straight through a water jacket.

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