The guy that sent the head in is my hero! I am a professional head porter and still I would not have big enough grapes to have my heads publically assessed by another pro. Allthough I wish I did. I know it would be helpful. I am sure I would learn from it also. I just wouldn't. So good for who ever that person is to be willing to do that. 👍👍👍👍👍👍

Before I hop in the dragster and get busy I wanted to watch this. I been racing my entire life. I have met a ton of engine and cylinder head guys. Basically some of the biggest names in drag racing at that. Not one of those guys have said anything so in depth and knowledgeable. It's weird because it's KZfaq, but I'm very seriously considering sending you my dart pro 1s. Anyway thanks for the video. Great way to start the day.

Props to the guy who sent it in. a few small changes and the ports will come alive.

Like you said, it took a ton of guts for this guy to send these in. However, it will have been money well spent. Kudos to him on making himself vulnerable in an effort to learn as much as he can. Best of luck to him.

Great constructive criticism Eric. You're certainly correct with "starting out". We all suck starting out or at anything new. How we translate the criticism is exactly how we will succeed or fail. I can remember the first head I asked an instructor to flow and evaluate 20 years ago. My pride shrunk, but I took what he said and dove right back in till I had a badass head.

What would be cool to see now are the effects of doing the recut valve job and the Ferrea valves with the existing porting. BIG kudos to the individual who sent this head in so we could all learn!!!!!

I port 2 strokes, But a few pennies dropped for me watching this. I have been tinkering for several years but recently I have been getting some serious gains and if I was honest I'm not exactly sure why. Watching this has helped my understanding and I really appreciate you taking the time to make this video.

One of the best videos you have made!

I really like the video, and you are right: a golf ball is different as an intake. But, it has a different effect on the golfball then you mentioned. It has to do with the spin of the golfball, pulling air behind the ball, causing an unwanted effect on the backside of the ball. The little vortexes created by the dimples make sure there is a better flow around the ball, preventing flow separation. We don't have anything to do with flow separation (unless you have really bad edges inside your intake side). As far as my knowledge goes: every head has a different optimal way to improve it. Different methods get different results on different heads.

Where were all of these fantastic informational videos back when i was building engines? Ahhh the 80's. What a different planet that was lol

I believe from now on i wont grind on my heads other than grinding minor imperfections off! Ive probably killed flow on all my heads! After watching your videos your a true artist in my opinion!

ive been porting for years i started about 35 years ago and spent some money taking joe mondellos course that guy taught me a lot ! i can tell just by listening to the ring of a grind tool how close you are to going through a head into water ! ive even dimpled ports on intakes and heads for specific situations dimpling actually works well if done right

Props to this guy. I did learn quite a bit from this video, having recently attempted to port my first set of Big Block Mopar heads. I wish I would have examined the short sides better on both intake and exhaust. I was honestly scared to alter them too much. Now I have a better idea on what to do on the short side radius of the next set I do. Great video Eric. Thanks for the info.👍

great that you have a willing customer to offer their craft work up for analysis for us all to observe. great insights and great content

He's got guts but he's smart learning all the trick from you .thank you for sharing your knowledge thank you

I've been messing about with this stuff for years, mostly old british iron, and I've learned many of these lessons the hard way! and your video sums up really well some of the most overlooked aspects of porting, and it's not overly specific advice either, as most of this applies to almost any engine. There's a lot of porting 'experts' that don't get the basics right, and will argue about the silliest things. This is just humble and honestly won experience distilled, Very nicely done. Thanks Eric!

Beautiful explanation! I am currently reading/watching everything I can to get ready to do some head work on my first engine - a little 2.0 Toyota 2S i know it's not amazing but it's what I've got - and this is probably the most informative video I have found thus far. Thank you

Awesome video Eric. I learnt more about porting from your analysis here than anything else I've read or watched. Thanks for taking the time to help out us amateurs who do this for fun, but want to get as good a result as we possibly can. Equal thanks to the guy who was brave enough to sent you the head. Doing so has probably helped more people than either of you realise!

We all start somewhere I wish I had someone like you explaining head work when I was a apprentice, great video, all the best to you and your loved ones

Excellent video! And kudos to the sender. The perfect learning material. That head contained basically all the normal mistakes that can be made while porting, and you found all of them and added ways to fix them. Everyone makes mistakes, only better ones learn from them.

Thank you. I find the information useful and reinforces what is important and what is not.

This right here is what makes KZfaq an awesome resource!!! A chance to get free expert advice from a professional! You can literally look over the shoulder of a master as he works and gives you advice. This is priceless👍

porting my first heads. Wish I would of seen your video first. Learned a lot. Thank you. Going to have to go back and look at my work. Think I made a few of mistake. Figures crossed that there are minor.

Eric, I think you handled this in the best way possible. Good, constructive insights which will allow this person to actually progress and become a better head porter.

I’ve had / have heads from Meaux and from Morgan. Both are so different… I don’t know what to believe. I’ve had CNC heads from the big 3. Both the Meaux and Morgan’s seem better for the application I used them for. One set looks like it was ported with an ice skate and a brick. One set are ported so nice I wear them around my neck on special occasions and when I get dressed up to go to Sonic. I have had both sets flowed by an individual that claims that he could fix them for me. Thanks for these videos. Keeps a guy thinking.

Awesome info!! And ty for the guy that sent in his head for the evaluation. Just saw my last comment . I’ll be rewatching this a few more times .

Very good video. Thanks to you and the guy that sent the head in.

This is gold thanks a ton eric and whomever it was that sent these in. :o)

another great video from Eric. Lots of good info ! and props for that guy who send the heads !

The thing about the golf ball is, the turbulence on the surface does not actually reduce friction. What it does do is essentially give the ball vortex generators on the trailing edge, reducing the wake size, and thus the drag force on the ball. It has no application for cylinder heads, car bodies, etc. There's a reason no one does it.

Recently ported and polished my first heads to for the build my channel is centered around. Learned a lot , wish I knew more people locally that had experience porting heads to get more of an analysis from.

I do the same thing with sand paper by hand lol been porting for 25 years and your spot on!

I was lucky enough to meet and hang with my mentors mentor in the mid 70's. His name was Jocko Johnson ( Heads by Jocko) a gearhead who considered himself an artist Harley Klentz my mentor and Jocko taught me basics of head porting and ive been useing their by "seat ot the pants" knowledge and technique to port my own heads. You Sir have revealed the intricacies and technical measurements required that have escaped me ever since. Im like a little kid again gorging on your expertise and knowledge . It's all well delivered and understandable. Thank You....

Great information. It gives me more to think about when I look off into nothing and become consumed by deep thoughts of how things work.

Eric's work is great. I watch a lot of your videos and lean a lot. I also follow you on Speed-talk Keep up the great work.

. I enjoyed every minute of this instructive video, thank you Eric !

That was really informative! Thanks to Eric for making the video, and to the viewer for sending in the head. 👍

Great science and teamwork you will increase my skills... thank you and porter for this inside info !

It would be awesome additional information if the owner asked you to put a proper back cut on the valves and smooth out the apex of the ssr removing the burr finish in that area. Then reflow to see differences. Thanks for your videos Eric. I appreciate those that are confident in their craft to share information.

Great Video! Awesome information.

Good stuff here!! I give the guy who sent his head credit for having guts to do it! I remember my first port job and it was ok but I really had a twist when I did my first tumble port design. 4 valve direct injection motors are radically different. Go too big on the flow numbers and it kills power from lack of fuel distribution unless you convert the car to port injection. It can’t be done on alot of cars so it’s not easy finding a balance between them to make power. A lot of good tips here. The short side shape makes a big difference with direct injection engines as well.

First pair of heads I did was on my own truck. No misfires leaks or nothing made about 30 more horses to the rear tires.

As an older guy I remember when the Bow Tie heads first came out and everyone hated them and said they did not work. They were cutting the floor down like the old 461 and 292 heads were done and shooting the flow across the back of the valve in a narrow stream. At the shop I worked for we went higher and wider with the port as it approached the bowl. We left the floor high allowing the flow to spread over the valve diameter. This cylinder head appears to be an updated version of the original Bow Tie heads. You pointed out the push rod area as a place that is easy to over grind. Crower cams made rocker arms that were offset allowing a builder to cut through the pushrod wall, reweld it and make the port .100 wider for a straighter port. Over the years GM tried to overcome the problem of the siamesed intakes by rolling the heads, changing the valve angle and raising the top of the port to improve the approach to the back of the valve. Back in the early eighties a top Nascar engine was 625 to 650 hp. Tonight I watched some videos of LS engines making 600 hp to drive on the street without drastic modifications. Taking a sanding roll loose from where it is glued together and making a flapper will allow a porter to smooth a ridge on the short side radius of a port without removing a lot of material.

Regarding the burr finish (or not) affecting fuel vaporisation. One difference between a port and a golf ball is the temperature. A golf ball operates at relatively low temperature. A cylinder head operates at a temperature well above the vaporisation point of fuel.

Excellent presentation. Fuel separation/drop-out seems to be almost entirely from 'dead air', where there was a bad port shape and/or bad metal removal that resulted in the airflow leaving the port wall. The valve and valve seat makes a HUGE difference on lower lift street engines, I've seen some 'know it all' wannabe home porters making a horrendous job with large amounts removed apparently at random and with very wide seats which choked the marginal flow - compounded by worn guides!

I ported the heads on my 1989 Ford Bronco 2 and port matched the upper and lower intakes. Factory casting finish and upper to lower intake match on those little 2.9L engines are terrible which caused restriction and turbulence. The work done made the engine run smoother and had quicker throttle response. May have made a very slight uptick in HP or TQ but not really noticable. What was noticable was #1 throttle response and #2 engine running smoother.

You helped him a bunch, and me also.

Best information video Your Best Video Best Video to help shops that still build first generation small block Chevrolet. Also shows your depth of knowledge. Thanks.

I must say that this man knows his shit. That shit being making power with airflow tuning. The in depth explanation from years of experience is apparent to say the least. Im an amateur racer just looking to make as much power with what i got. I got a 4 banger and a brain. Thats a start.

Love this off his first advice

Awesome info!!! I would like to port one of my heads and send it in one day.

Thanks Eric for another nice video

Really nice port work.... polish the exhaust ports to a mirror finish and they will flow really well...if you put a super charger or turbo charge the engine then you can also polish the intake ports the same way....

The best thing to modify to gain flow is the shape of the valve head. Most valves are shallow cone shaped,, a steeper cone will reduce turbulence and increase airflow.

The rough finish inside of a tube increases the rugosity and the surface coefficient, resulting in turbulent flow. In engineering, we use the Reynolds number to determine if a fluid or gas will be in turbulent or lamina flow. The goal is to have the ports designed to eliminate as much resistance as possible to the flow of gasses. There is a relationship between pressure and flow whereby the easier it is for a gas or liquid to flow through a tube, the lower the pressure becomes. The point of porting is to optimize the flow so having a rough surface finish will result in turbulent flow which would be counter productive. You could argue that this would help atomize the fuel however the problem is that as soon as the fuel vapor enters a low pressure zone of the eddy, it will become a liquid again. The best option is to have as smooth a finish as possible to reduce any restriction to flow so that you reduce high/low pressure regions allowing the fuel to remain in a gasseous form and flowing as efficiently as possible.

I hand ported a set of 327 heads back around 1975. Back then I was told the drag racing rules only allowed porting 3/4" deep from both the intake and exhaust ports. It took me about 80 hours with a Dumore grinder and I ported them all the way from the ports to the valves and I polished them too.... these were cast iron heads. Back then, the concept of leaving a "reversion dam" in the bottom of the intake side was supposed to be the latest and greatest in cutting edge design... and the real conversation back then was whether or not to make just a single damn or leave a double dam by leaving around 1/8" to 3/8" past the 1st damn to the next dam was actually better than using just a single damn. From your video I would have to assume that the reversion dam idea has been dropped.

As a professional skydiver, and a damn good mechanic, I can totally appreciate all the physics in this video that I dont understand, yet totally do, lol!

Racers will do all kinds of wierd stuff. We used to knurl crank throws on 2 stroke bikes to turbulate/ possibly increase air flow. Grind and polish and knife edge cranks and rods.

That was probably the most educational head porting video ive ever seen , and ive seen ALOT of them ! Nice job . Curious , if u had to guess , how much power is being left on the table between running his heads as is , and changing rhe things that u talked about if u had to make a rough guess based on your experience with these heads ?

On did my first mild porting job on a set of 993 gm heads 10 years ago on a set of heads I bought in 95ish from Arrowhead, I ended up with a small bump on my short side radius I was like oh wtf that's not good so I cut a dynafile belt in half and just pulled it back n forth until it was a nice smooth radius, fortunately I didn't do it on all of them I caught it pretty soon. Arrowhead (a division of Indy cylinder head as far as I know) did the pocket port for $100 extra I opted for (along with optional $100 2.02/1.60 s/s valves and $50 screw in studs) so it was already done all I did was a small bit of smoothing to reduce ridges because it was pretty crude, looks as if they got the correct shape but not a lot of attention to detail. They actually make pretty nice power for mild SBC. I did see the bigger valve can actually hurt flow without some deshrouding but with only 9:1 I wasn't Shure which was more benefitial....more compression or bit more flow.... But I'm rebuilding it and I'm buying pistons with a mildly domed pistons so now I can do some de shrouding and still have 9:5/9:75. I know I could just use vortec heads and make more power but I think making decent power with old iron has a cool aspect and it's always run really strong in current configuration so why go through the hassle of modding vortecs and changing my intake even tho you said the Torker 1 is mehh and I agree not optimal it seems to work fine, it does have a 2" spacer...helps don't know. But I smoothed all the runners, guide boss radius,polished exhaust runners and de-burred chambers work good for first mild porting.

You are giving out gold hear Eric,, I would weald or epoxi in the short turn area and buy the best valves I could for this head. back cut and under cut stem.

Interesting video Eric. One suggestion though. I believe it would be really beneficial to annotate your results tables with percentage differences when making comparisons. Eg plus or minus percentage flow differences. +1.2% is fairly insignificant, + 9.2% is huge. I find I keep having to scan back and forth and mentally do the percentage calculation very quickly while the video plays. An additional 3cfm on 100cfm is far more significant ( and worth while) a change than 3cfm on 300 cfm for example . Also another forlorn request please for a good video on porting 4 valve heads. I think there will be demand. Thanks anyway for your video presentations. Mark

Too bad we couldnt get the valve job done by you and see the numbers improve too. Great tips really helps

Please do a video on valve jobs and flow. I've seen so many different thoughts on this from narrowing the seat, pushing it out on the valve, five angle and more.

That does take guts to have your work checked by someone else like this. You done a great job of explaining what could have been better with out being negative. You've earned even more of my respect. I have ground on a few heads and used to modify 2 stroke chainsaws. It's been a few years though. I'm getting ready to work on a set of GM 128 L98 heads for a little 339 (305 with 3.75" stroke) I'm building. This info is priceless for me to get on the right track to get some decent flow out of those heads.

Awesome video Eric

If you're not totally honest, the customer doesn't get their money's worth. I say you did a great job in evaluating and pointing out their work, without insulting them. That's the very reason I would have someone critique my work, so that i could learn more without being beat up about it. I think this customer got well more than their money's worth.

Heard the big chief mention your name. Hopefully we get a video on his heads

I think all of us are looking up to this brave man

So he actually did a good job of porting. Some better valve and seat cuts should help as you said. Thanks Eric!

Used to be a mechanic, one of the shops I worked at would offer this service so had alot of practice. Had a customer that was NOT happy with 60 grit, or 240 grit, we had to get intake AND exhaust to 20000 grit and polished to a mirror... He later never paid his bill after the boss let him pay it off slowly. I'll freely admit it took me forever to get it to his desired finish, from memory 2 weeks of basically 8 hr days as id think surely this is good enough...NOPE he would find an imperfection or it wasn't mirror like enough. We even had to tig inside to fill casting holes countless times, grind it out, buff it up, then he would see a tiny and I mean tiny casting hole. If my boss hadn't talked me out of it and bribed me a few times I think I'd have quit by the second "not good enough". Hate to know how much materials alone went into it, let alone the man hours he didn't charge for (seriously the whole job was only 800 a head he complained alot but 2 weeks is stupid long and pretty sure the boss stayed late alot to help, and ik I done a few very long days as I was in the groove and lost track of time) also don't be that guy/girl that expect that kinda finish, let alone doesn't bloody pay.

6:58 from my understanding of fluid dynamics and aerodynamics I just want interject something here. Turbulation, with the coarser burr finish the flow is staying my turbulent and keeping the fuel in suspension. It is impossible to get laminar flow through a cylinder head intake or exhaust. So making the flow as turbulent as possible it will keep fuel and air charge well mixed.

A tube 2 units diameter will flow 16 times as much air as a tube 1 unit diameter. A small reduction on any port makes a far bigger difference that the measured size would suggests.

Good video Eric , and that is why I would leave porting expensive heads to the experts , LOL .

Once upon a time I was a 1/8” dremel grinding kid, making things bigger and shiny. Fortunately with all the variables of street racing, my hog-wild approach was lost in the “noise”. They’re probably some of those heads on a blow engine in a rusted out carcass patching a farmer’s fence.

I make the port on the head smaller than the intake manafold when I scribe I cut to the inside on the head and the outside on the manafold.

I would like to see you make a video of how to properly make the measurements correctly.

makes sense for burr finish making more torque, I believe at lower speeds fuel will fall out of atomization faster, however find it easier to become reatomized at lower speeds? I think?

WOW! I JUST LEARNED SOO MUCH FLOW TECH. Thank you for this video. Now where did I leave those Jag v-12 heads? SUBSCRIBED!

I 0ort r53 mini cooper cylinder heads , intake manifolds , intercooler horns AND throttlebody and it makes AWESOME power gains

Really interesting 👍 Regarding the exhaust. Some say they listen to the sound it makes when the air goes through. Is that something you do? Maybe something to try and talk/show in a video?

Curious how that back cut affects atomization. I'm always timid to follow the flow bench instead of the dyno.

Good video! I'm about to take out my motor today for a freshen up and bearings/pump and the head was my concern anyways. I wanted to see if I can make some improvements or at least correct some problems if any. Port/valving tech is always a concern on a I6 head lol.

Very constructive criticism Great video. I personally learned allot. 👍👍 I've ported a few sets of heads with decent results, Incidently my last name is Head 😄 .... go figure.

Great video ! Question... you said not to raise the roof, what if on a head you need to cut into the roof to port match the intake, would you do it or not? Never mind... answered my question in the video. haha :)

On the subject of valve jobs. If someone sent in a head they ported with a stock valve job would you do a flow comparison of stock valve job and then do a valve u feel is correct? I would find that interesting to see

one thing you got confused: air going on the tightest part of a corner - that's the slowest moving air. Because the fluid dynamics will always try to "equilibrate" the atmosphere, therefore the air moving the longer distance will have to move faster to balance pressure. AKA air on the longest side of the corner will be going faster. Just like over an airplane's wing.

I have a pair of Pontiac 13 heads and I noticed that the exhaust port is a little offset to the valve pocket is that to create a vortex? I never ported heads and I am trying to learn as much as I can before I pick up a grinder and your videos are super. As a beginner I think I should just give them a street pocket porting nothing too drastic. I'm trying for 400hp out of a 400 Pontiac. Stock quadrajet intake and reproduction ram air three exhaust manifolds. Would Swirl polished under cut valves make a big or small difference

I would love to see an actual dyno test on a CNC finished port versus polished.

So I noticed in the Cylinder head down in the Chamber there 2 holes 1 looks like it has threads and other just looks like a hole what they used for.

properly undercutting valves then swirl polish can help enough to mean winning or loosing too !

Thanks for the link to the end of the other video and your explanation, I can see your thinking now. It does raise another question though - Let's make an example - Head will have 700 lift on the engine, everyone wants to compare so test at 28" no problem. But wouldn't it be more realistic to do your stability test by staying at 700 lift and increasing vacuum ? I'd appreciate your thoughts as I'm trying to understand the practical re-creation of a running engine scenario to flow testing as applied on the flow bench ?

Great Engineering.! I am also modify & tune motorcycles engines for RACING in INDIA. I appreciate your Good work..!!

Some good advice 👌

Are we forgetting about the “Boundary Layer” the port texture creates? The boundary layer actually helps by creating a layer/cushion of air to help the fuel/air charge flow with less restriction and stay suspended. At least this is the theory I’ve followed with success. JD

I’d love to see you do some 4 valve stuff. There’s very little info on porting them. You have a little less freedom because of how small it is around the valves & from factory the bowl blends are often pretty bad.

Great video

I changed my bbf to 5 angle was a good increase in flow 2.50 intake

I never take anything as you being harsh man. What I understand is that you know what you're talking about, you wanna get the point accross and teach and there are way to many hard headed people out there who think they know when they don't actually know. I Think one of these days i will ship my ead to you just to make a video on and hear your thoughts. It might be great or it Might suck lol. I'm pretty good on my Short sides, bowl to seat blending and reshaping around the guides. But Like I said I am not pro but I try to be.

When you were talking about back cutting the intake valves it reminded me of someone once saying a guy should front cut the exhaust valves. And that the cut should be a radius (rounded), have you ever heard of this? Does it help exhaust flow?