We are privileged to have you educate us on all aspects of engine design. Please keep up the work.

Those guys are lucky to have you teach them.

Thank you for being so generous sharing your knowledge! If I were younger I would be in your school. Remember this. Your not giving away secrets. Your creating a industry. Making old designs more efficient . I'm sure the original designers had no idea what was left in those ports. Please keep sharing.

Always a pleasure to see your videos.

"Cylinder head development engineering" - right on! I've been a fan of David's ever since I first read a book of his 20 years ago. I could pester him with questions about engine theory forever.

Another great video, thank you so much for taking the time to make these.👍

Great info DV! We appreciate your time and effort to help us build better Sir !

After 40 years of reading his books and now watching his videos I'm still learning like a beginner

Thank you. I do appreciate you giving us non-professionals a taste of the depth of what really goes on in engineering, well, any engine, certainly including race engines.

He teaches as a good teacher, thanks for sharing your knowledge with us.

I have and have read all your books and refer to them often. Thank you and please keep making these videos.

I knew a lot of what you explained, what I didn't know was the why, thank you so much for taking the time to explain it in detail.

Just built a stoker bbc and used your book as a guide. Wished that I had seen this video about 2 weeks ago. Will have another in the works shortly. Love the series!!!!!!!!!!!!!!!!!

Oh, it is a great treasure to hear, rather than merely read, Mr. Vizard speaking directly. We are better served, first to read, but also now to listen. I am reminded of David Bronowski. Both Vizard and Darin Morgan explain the reversion that occurs when the radius is too short and the flow flies off the turn. It is wonderful actually to be able to hear these experts.

So sorry about the loss of your daughter. Thanks for sharing your technical insight in these videos and your books.

The subject of good and bad ports was brought up by one of my close friends. The 440 cfm quoted is for the bad port. The good port, which is what is most often quoted in BBC porting features, actually went 446 cfm. Not to shabby for a regular 24 degree head design eh!!!!

@trdscfjc

Жыл бұрын

The EngineQuest heads have not been available for the last couple of years, Dart also stopped manufacturing their iron heads 2-3 years ago, there is only 1 aftermarket supplier left and that is World Products/PBM, and those use integral iron valve guides. Unless there are others?

DAVID THANK YOU FOR AN EXCELLENT VIDEO YOUR THE KING

This man has been one of the greatest in his field since I learned to read and is still unmatched!

Hello from Upper Michigan U.S.A - We Love watching your great videos. Thank You for making them.

Excellent resource. Thank you so much.

Thank You Mr.Vizard Great video !!!!!!

I have to hand it to you for being very cool & not driven by Ego. You didn't dump on the guy but more importantly you understand the Practicality of making a cast-iron head work better. Thank you for keeping it real....

So nice to run across your site David. I just hope you will put together a book with all the great information that only you know. Thanks for the great video too.

Hello Mr. Vizard I saw you on Uncle Tony's live show. I came here to learn all I could about Big Block Chevy heads. Thank you for all your knowledge!!

Always like your books and videos

Thank you for your time, we are privileged to have access to this information.

Good video to help any of us, who wants to port our own heads, learn the do's and don't of 454 chevy V8 head porting.

Hey, David, I'm watching these videos of yours with the interest that's coming, I'm subscribing to your channel.

Amazing info, thank you so much for this priceless knowledge.

I will probably never build a performance engine but you make it understandable and fun to learn anyway.

very good class teacher

Thank you DV, I am a bit late to the party 🤭 but the content is spot on, loving your insight to the intricacies of engine building and design, if I was in the US I would defiantly make the pilgrimage to come and say hello!

Thanks for the video. Keep them coming

Followed David's guidance as a 17 year old building my a series mini engine, his bible for the A series is just that . Thanks David

@TurboMinicom

3 жыл бұрын

I agree, if it wasn’t for his influence I wouldn’t be doing what I do.

Thank you! I read and archived everything you said in Popular Hot rodding.

Love your books Vizard!

I am ready to learn!!!!

Great video. Id love to see some videos from you, in regards to the a series engine. I have read your books multiple times.

Thanks David I've always learned so much from your books and videos

@jerrya2367

3 жыл бұрын

Very good

Eagerly awaiting your next book.

i could listen hours to David, unfortunatly i can not afford a seminar that far away.

Great video David

many thank's yo you Mr. DAVID!

Just came across your channel. I like it

David a love all your videos I'm trying to go to your class hopefully there's one in August and I'd love to go to your 2 week course on head porting

Thank you so much

I thoroughly enjoy your content .I use these heads for bracket racing .in my mind there's a benefit in steel heads ability to hold heat as compared with aluminum as we run methanol.i don't need max horsepower .I would love to see how much my et would improve buy having improvements such as you have made here.very nice work so thank you for another interesting episode

Nice work!

David has the Mathematics and Physics nailed,, i can port and pollish a head but it wouldn,t do a thing if i dont know where to cut or leave. Steve in Australia

Thanks for your yery creat findings sharing and also doing

I could listen to David for hours.....oh wait, I have been

19:30 I dig the great head of hair you got. Rock it 🤟

Thank you for sharing your knowledge!! I run BBC in my strip car and am building a 69 chevelle for the street.

As I have commented before on some of your earlier videos; it's not any specific alteration or modification I can copy to make an improvement. It's passing on a concept, practical or theoretical, that I can then apply or expound upon, to numerous differing situations. Thanks much for the insights. I want your flow software.

Thanks Real Helpful!!!!

DAMN this is the best explantion I have ever heard regarding the short sides of the BB head. It is why the whole D ported exhausts were developed... to raise the roof beginng aft of the guide to reduce the "wall of turbulence" or AIR WALL. IT is why BB's benefit from a correctly designed scavenging headers SO DRASTICALLY... think about the L88's with open chambers in late 69. The Hp was up by something like 150 with headers alone. The backpressure combined the the wall of turbulence severely dilluted the cyclinder charge. NOW I see why you said what you said about the vortec head, PENT ROOF CHAMBERS!!! I had Dave Crower design a solid roller for a 1969 Z28 302 chev. with nearly stock 186 heads. He went through everything with intake runner volume and flow numbers every .100 from .100-.700 valve lift... the engine made 350ft# torque from 3500-5500 and peaked at 390hp Made 15# vacuum at 900rpm idle. Solid roller with HIPPO lifters (high performance pin oiled), cam and everything has been in the engine running on tne street for the last 15 years. 15 or so thousand miles. .636 valve lift intake 276 duration .636 valve lift exhaust 282 duration On a 112 centerline.

Awesome lessons learned from you. I understand how critical max airflow/velocity is crucial for building/making max HP/TQ in racing engines. I (like many others) are building engines for cruising (station wagons, sedans), not just for shows but cross country as well, and pickups for towing and cruising. How critical is it really that I/we maximize the size of the ports and airflow? In our driving we want to maximize the mpg's and still make as much power as possible (within reason). I am building Ford 429/460's and 390/428 FE engines. Thank you for all your excellent videos and lessons you have provided, your knowledge is astounding and impressive

I think I got every book David has put out bar the latest 2012 porting one. At one point I used to scour two major auto bookshops around my area for the most recent car books and subscribe to every performance car magazine. The bookshops are gone and the car magazines are mostly no longer. This generation is not interested and in the next few decades the ICE will mostly be replaced by electric motors. Nevertheless it is great to see David imparting his knowledge for us all to enjoy.

Thank you for showing telling, and I’ll see ya next time see ya bye bye.

Just on blending the valve angles , maybe it suits these heads but I see sometimes the sharp transitions help , Any videos on 4 valves , everyone says where there not the same but no one addresses it , and will valve ratio change much with boost Keep up the god work

Thank you Sir your knowledge is priceless would love to see what you could do with 1 of the most popular oval port import speedmaster heads with 305 cc intake runners and 2.25 valves. That's all manny of us can afford.Thanks

Laying the chamber back to allow the exhaust gas to utilize the front of the exhaust valve works good on alot of cylinder heads they are practically blocked off by the long quench area on most heads. Visually the only difference i can see between 243 LS heads and prior head casting is that area is laid back and rolled over from factory.

Its just amazing now you can buy a set of alloy sbc heads, manifold and roller rockers off of fleabay for less than a set of new or used vortec iron heads cost

Nice stuff. I wish I could bounce some ideas off you some time

Excellent, thank you. Have you ever ported Gen 6 96-2000 L29 454 heads? They have those dang 'swirl' lumps in the intakes.

This is the only utube channel that I have a copy book and pen ready. Any chance of running another head porting or head evaluation video and discussing the advantages of plug indexing? Thank you.

I can't thank you enough for the information you provide in these videos. I would only like to ask, what of the big block Ford DOVE-C head?

I have that book and it's great book to have

David Wizard ❤

Nice to hear someone mention the lsa topic.

@scottvincent7666

3 жыл бұрын

Wider LSA is more beneficial under certain circumstances than tighter LSA.

@Torquemonster440

3 жыл бұрын

@@scottvincent7666 yes.. fuel economy.. driveability.. broad torqe curve.. engine vacuum... NOT for all out POWER !! Which is what Mr. Vizard is educating people about.

The most valuable lesson appears to be the efforts used to flat out impede on reversion, drowning the following charge with burnt fuel is obviously enemy # 1. That modification alone speaks volumes, if you could only make one change per cylinder... my guess would be in the efforts used to put the brakes on reversion first and foremost. (Stomp out contaminated charges)

David, regarding the quench area on the head, have you ever tried running a shallow 1/16-3/32" deep groove from the cylinder edge to towards the exhaust valve/sparkplug (with the shallow dishing you have done around the exhaust valve the groove may be 1/2" long at most) it is said to allow the back corner furthest from the chamber pocket to squish out and even up the mixture by causing turbulence and get a more complete burn of the charge?

Wondering what chamber and bowl mods would you make to a set of bbc closed chamber heads specifically 206 castings? I don't see much in the way of modifications to closed chamber or ppl using them

Always interesting. 👍 Got the books also. Its just a shame that almost everything is in relation to V8 engines. Im working on V6es so I have to ”translate” everything over to those engines.

Soo many channels on youtube concieling this hidden gem

How important is the polish , casting smoothing vs. a cnc job on the same head? Thanks

Do you have any ideas or tips on the closed chamber heads like the 206 casting?

I'm curious if DV ever considered redesigning the v8 crankshaft stroke timing such that there would be no intake or exhaust pulse interference. Does the flat plane crank shaft accomplish that?

Yes online school would be awesome. With zoom anything is possible. Make the interweb recompense for all those lost book sales haha. Might be a nice lucrative sideline for you Dave as this info junkie wouldn't hesitate to transfer them £££'s in your direction and im not alone i suspect. Wouldnt mind getting my stack of Barras singing the 1000 plus kw song. Video much appreciated by the way. Props!

Thank you for such detailed BBC head info. I'm building a 439 ci, 427.060 over BBC. It's a Marine application so would like to use iron heads. I can acquire new World Products Gumpy Jenkins 269 oval port heads. These heads would be no complete so would be ideal for a complete build up along with your porting program. I'm intersted in having these heads ported and assembled with valves, Springs etc in your shop/school. I'd appreciate your response and help in my boat engine project, thanks again.

Hay David first I want to write that I love your work I enjoy doing what you do but I’m a hobbyist so I don’t do as much as I would like. I like to understand. What I want to ask is I’m into early vw engine 1600 and the standard crank is a non counterweight do you think I would do better with a counter weight. Thanks 😊

What do you do to the quench area on a 300 ford fuel injection type combustion chamber

I'm sorry if I missed it but do you address the holes cut by sealing them up? It doesn't effect flow?

I'm often undecided between single or dual pattern camshafts for the BBC, what is your view. Thanks.

Interesting. Back in the 70's, the magazines often said it was called the Rat due to the crank snout resembling a rat's snout.

@shoominati23

3 жыл бұрын

I think they called them a Porcupine in the beginning because with the rocker covers off, the valve springs resembled a porcupines quills .. really the blocks arent hugely different in size though

Hello, first I would like to thank you for sharing your amazing knowledge with us. My question is I have a 1970 Chevy kingswood estate wagon with the OEM N numbers 345HP BBC 454 code CGV. I would like to wake it up some but keep OE Heads do you have any suggestions ? Please Advise and Thank you once again. Cordially, Ed

When ypu change the intake port how much does it add to the cc of the port?

There will never be another D.V. The best period !

Would the chamber mods shown here work on 781/049 GM oval port heads as well?

Do these same principals apply to big block chrysler heads ?

Is there anyone that you would recommend that does porting on Iron heads?

Do your flow numbers correspond in an actual real motor running?

No Prep Stretch:- At a given CR what torque outputs were you achieving? Give me some CR's and cubes and the torque achieved at that CR/cubes

what was the casting number on that cylinder head? I'm amazed at the results on these heads that most people would throw in the trash. You are truly the master

@DavidVizard

3 жыл бұрын

Travis, don't have the heads anymore so I cannot say. Sorry!

Is that Y 3 vavle head work little better?

How do these seat blends affect fuel separation? I recall radius jobs on intake being 'bad' because of some reason about fuel not shearing and sticking to the chamber wall, and although it's not a radius job, having not-sharp changes does start to approximate it.

@DavidVizard

3 жыл бұрын

Skippy, there are photo'e of the fuel shearing of a radius intake seat in the head porting book of mine, Under real world pressure differences the fuel shears just fine of a radius entry seat,

The flex at @37:27 tho 😆

You should have a online porting school, i would pay good money for a online school ,

Radius on the intake valve seats will cause the fuel to separate from the air flow. Sharp angles on the intake seat are not only preferred, but perform better and keep fuel suspended in the air stream. Newer design heads use multiple angle seats on both intake and exhaust, as well as multiple angles on the valves. This has proven to perform over radius seats every time. Angles used, width of angles, etc. are heavily researched and on many heads can be proprietary. You won't find radius seats on any decent performance head manufactured today. Additionally, when the valve angle will allow the top angle and combustion chamber angle off the seat to be the same, or in other words a continuation of the valve seat angle, flow improves in the mid lift ranges and power also increases..

We use to put a filler tongue in the bottom of the exhaust outlet on closed chamber heads. It helped, but the open chamber heads didn't need it. I can see why now, thanks!.