Around 30:00 you start talking about LSA... I agree with David Vizard's experience that LSA is more critical than lift and duration. That one should select an LSA first, then the overlap, and THEN the duration and lift be what they are to acquire the first two parameters. My understanding is that LSA is so critical because the whole objective of building a performance engine is getting maximum cylinder filling based on the parts you're going to use. The LSA accounts for using the exhaust pulse/flow/vacuum in conjunction with the head's intake flow characteristics to maximize this cylinder filling. Then select your overlap to get the idle vacuum needed, and where you want your peak power output in the rpm range. Naturally as engine speed increases, air and fuel do not increase their speed at the same 1:1 rate, so the engine would need more overlap to get good cylinder filling at higher engine speeds. That selecting a cam's specs this way will result in a given performance engine that makes more power (tq &hp) EVERYWHERE in the engine operating range (ex: "2000-6000 rpm") than selecting a cam without the optimal LSA, while instead focusing on duration and lift... As it does seem most people suggest how it should be done. Even the cam companies. Makes perfect sense to me.... Great video... Thank you!

I am a subscriber who has no intention of rebuilding my own engine or even getting a rebuilt engine. However,, for me, the channel provides the best way for me to learn about engines. This video was a great way to see how this all comes together. Thank you.

Just bought a C5 corvette to use as a drift vette/daily commuter. Been looking for an informational video on camshafts and stumbled upon your channel. THANK YOU so much for putting out such concise and well explained videos packed with knowledge! I've learned so much from this I honestly feel like I owe you a beer at least or something! Lol

I wanted to say thanks for putting this video out. I got out of building engines for basically a few decades and recently wanted to start doing it again and have forgotten a lot of this stuff.

Fantastic ! I want you to know that we all very much appreciate your teachings and how you explain the function of an air pump. I’ve learned so much from your channel. I built my first engine by watching my vintageiron!! And it is a ground pounder!!! Just want to say thanks, I couldn’t have done it without you. Luv the video!!! Keep keeping it 100!! Thanks

Great video, thanks. Ed Iskederian wrote a great book on cams back in the 60"s. You can still find them online.

What a great video.!!! A great expansion of the last video, which was also a great video. Thanks for the knowledge, and the willingness to share it.

This was a great video. Thank you for the knowledge about something so overlooked in motor building.

Bought myself what I thought was a dirt and oil covered 1967 Ford 390 FE, and thought I could rebuild it based on what I remembered from high school and what I learned watching you. But I think what I thought was a 1967 engine, turns out to be a 1961 MEL engine. From what I read this engine is not a normal engine, looks like I might have to start all over with my education. Oh well. Your videos are great. I see your UTI shirt. I went there in 1985 but took the air conditioning course. Thanks for the videos.

WOW, You laid it all out! I have built quite a few of 351W based engines, (I am a "FORD GUY" but realistically the "AIR PUMP" doesn't matter what logo is cast in the side of it!) and more CID per cylinder changes cam choice as well (A Radical 289cid Cam in a 410cid engine seems more much tame!)..I was guessing for that FIRST head, Flat Tappet, Nice Street "Cruising" Car (Like that 1968 Mustang you were working on w/GT40P heads, "Just upgrading a mostly STOCK 351cid Carbureted engine, with stock drivetrain") - *stock converter* .450/.450 on lift... and "Guessing" 218°/224° @.050...on a 110° LSA.. So I grabbed My Comp Book... In the Comp Book...XE262H cam is a good choice without making it TOO radical, has .493/.500 lift which is at the VERY high end of your "Example" .450 lift heads range 218°/224° and 110° LSA...but you could choose a different/custom grind, or go down to the XE256H and make that 351 a little more smoother at idle...I wouldn't but that's ME, unless there was a "NO LOPE" request. The D3OE 1973+ 351W Hyd Cam specs I have (Which Could be WRONG) are .416/.445 198°/208° @.050 115°LSA (Plus ran Really Retarded!) WOW no wonder those emissions engines were so LAZY!

this is great knowledge and seeing the math back it up really cemented it in my head

Yep, always have known you need to match the cam with the heads. Makes perfect sense. Probably why the top end kits are available, including the intake and timing chains. Good video. Thanks for sharing!

It’s close to your first video of this.. this is stuff we used back in early 80’s, if ppl will do the numbers they will be happy with there engine, we’ve built many of them using this, great video

This is, by far, the best overall explanation of the magical bump stick in one place, at one time. I think the only thing I could ask to add (unless I missed it) was the relationship of amount of valve duration overlap and exhaust scavenging as it pertains to clean combustion and such. But, that's kinda minutiae compared to the big ticket items of lift, duration, and how the heads play the pivotal role in potential horsepower production. Excellent, excellent video and information. EDIT TO ADD: LOL just started part 2. subject #1....... overlap and scavenging!! YOU ROCK

Thank you so much for all your videos! You helped me a lot to get deeper into all that "science" (beside some literatur). Currently building my second FE and thinking about to do a higher rpm setup. Best Regards from Germany- stay healthy!

Cam school! Love it. I know this is from a few months ago, but timeless videos. Wish you were closer, have a Pontiac 350 that I'd love for you to work on similar to the one you did in your video series. Loads of great info on your channel, really appreciate the effort that goes into it and the education.

Appreciate your videos, for REAL!! They answer so many questions! Thanks for your knowledge! 👍

Excellent set of videos on camshafts selection. Keep up the great work

Great job on this video. I'm getting ready to build a Ford truck motor & would have made big mistakes if I had not run across this video.

Damn...I feel like I was just given the keys to the kingdom! This will help greatly. Thanks!

Absolutely the best camshaft selection video EVER!!!!!!

Thanks for your videos. I like how you break things down to understand. Appreciate it.

This is a treasure video. I appreciate your work it's awesome you are a wonderful teacher man, big thumbs-up 👍. Cheers 🍻

The cam has always been a mystery to me. Thanks for clarifying this for me. I am looking forward to watching part 2.

this dude is bad ass ... rumor has it he has a grizzly bear carpet in his living room but the problem is its not dead it just lays there because its afraid to move ..

Hey buddy! Just in time! I have both a 302 and a 351 that I'll be working on here right away. Thanks for doing what you do!

Fantastic video and information. When you went to calculating all of that spring pressure on the cam I think the only way you would hit that scary number would be with all springs being compressed at once. Not saying that it isn't a significant factor here it just caught me a bit askew while watching the video is all. Thanks again for ALL of your great videos sir.

This is the best informational video I've seen on this subject. K.I.S.S. It is easy to understand and way better than that friend of a friend who just happens to be an expert. We know how that ends. Thanks again and let's keep the Legacy alive.

Great informative video my friend! Would you consider making a video of the gains to be had by just switching out rocker arms and valve springs without even changing out your factory cam? Alot of people seem to overlook the difference a good set of rocker arms make. Thanks again for all the knowledge you share!

Tons of knowledge packed into 47:18 minutes.....Thank you very much!

Thank you for making your vids, Super informative and direct 👍

THIS VIDEO that you have done, Myron, has to be your greatest. YOU have even shown us how to figure out how much power we can expect from an engine size by its head flow. WAY to put that knowledge down. NOW if you could show us how to predict how fast in a quarter of mile time to expect a car will be, and how to properly gear it so it would run the traps at peak pwr. I look forward for the vid of the Pontiac stroker.

Wow. Really enjoyed this video. Lots of info to consider. So you basically need to design your motor on paper before you decide to build.

Great video...and very logical in your methodolgy I enjoyed this video very much and learn something at the same time... thank you for posting it.

So good aftermarket heads for my 5.0L H.O. to replace the crappy e7 heads . Thanks for the insight , I'll choose heads before buying the Cam .

Holy snickies I learned A LOT with this video.. Thanks a bunch!!

Great information and it's this kind of information I could have found 35 years ago and I would not have a engine that I'm finally going to ger right

I love this channel. I learn a lot. Thank you.

Learned a lot about how to select cam shafts. Like the formulas

Great explanation of camshaft characteristics!

On my Ford 306, I chose a single pattern cam with a bit of overlap because I opened up the exhaust bowl and port roof a tad while smoothing it's transition to the exit. Granted these were stock heads with slightly bigger valves, I thought some overlap would help build some cylinder pressure to compensate for the low compression heads.....it has a lopey idle, but it revs right up toward 6000 pretty quick. It works okay with a manual transmission.

Good videos. I've watched both parts and now I know I have the wrong cam in my sbc 400. Its .30 over with flat tops. I felt a 400 needed compression and good heads so I used OEM Vortecs since they are better than the Camel humps. I used a .450 lift because of an equation I found years ago and because I didn't do modifications to use more lift. However it is a single pattern cam with 104 lobe seperation. I'm taking the cam out as soon as I figure out the correct duration dual pattern cam.

You are a great teacher thank you

WOW That is all great information and you did a fantastic job teaching this subject! Thank you!!

Thanks for your efforts making this informative video.

gm does build a street strip trans but i do agree that u build for racing or u build for the street . if u ever find a 400 turbo with 02xx welded on the bell housing u have a very good trans stock good to 800 hp i have 4 sitting right now have a another set up to go get 450 hp 454 with the 02xx trans for free running good . i put one in my 68 chevy pu and the engine is perfect for a street set up good sound to the cam runs hard put a 850 with a street weiland high rise and it came alive the trans is very good and solid shift has the 8 bolt pump heavy clutches stage 1 shift kit saves me a lot of money on builds plus u just can't beat the looks of a big block in a rig in my 68 chevy pu it fills the engine compartment all most to big the main fan has a 1/2 inch from pullies and about 1 inch from the radiator then put 2 pusher fans on front that comes with the engines set the wiring up for a serpentine belt alt. and can go back quick to internal or external alt

Great video & LS guys using stock heads can do almost all of this because flow numbers for head castings are readily available

Such a helpful video. And so logically explained. Thanks!

thank you for setting the record straight!

Great video, At one time I felt I needed to raise my hand to go to the bath room.

Using this for the cam selection for my 454... Great info.

Great info, I am all about the science behind engine building

The best videos out there! Thanks

Good information video if you don't go with expensive top end kits allowing you ability to design your own engine kit with your preferences

This video is amazing. Thank you for taking the time to do it.

Excellent information. Thank you sir.

Great video, I learned more from this video than I have in 30 years

Great vid. I’ll have to check the numbers on my Fox body set up. Has GT40P heads with a Comp 272 cam. Most numbers on that head show 198cfm at .600. Honestly I went with that cam based on info on the internet and the same combos other people were running

Awesome video! Would love to hear your thoughts on piston speed v.s. ring package

Thank you for this information. Very useful. How about a video on how to flow your heads?

Great knowledge as always.

A true aha moment for me. Many Thanks!!

This video is very informative I appreciate your videos

You are one smart guy...thanks bud...

You taught me how to degree a cam back in school. Good times.

Fantastic information! Thank you!

great info as always. could you talk about the difference between tri-y headers and 4 into 1. and whats best for what application.

Bro no homo, I love you, I would love to get trained by you. Right now I'm looking for a GM school, I want to be a engine builder. If I would of knew this I would of went to school for this for sure. Thank you man

So cool! Learned a lot

Either this is same video you re posted or I’m having perfect deja vu or the Mandela effect is real!

Dude, thank you. That was the best education online yet. Early 90s I only guessed at parts.

Awesome Info !!!! Thank you

Peter with great power, comes the right cam, heads, crank, air flow, pistons, carburetor, or injection system over build be safe.....

this is amazing. been reading hundreds of forums and getting nowhere. this is a scientific fact-driven approach. used this math to evaluate a new cam keeping same headers and saved me $ of money. will write a blogpost on FSB once im done. I haven't figured out how the intake manifold (upper and lower) restricts the air flow per piston in your formulas. e.g. if I have a stock 302 lower intake with 150cfm, that means I will get nothing upgrading the headers as the stock headers already get to +150cfm at .500 lift. would it just bake in the % air flow e.g. head_to_intake_%_airflow? PS - just one tiny note on the % of flow. in the video you mention dividing the higher number INTO the lower and confused me a bit. (wording issue with "divide a into b" vs "divide b BY a"). And rounding the 128/197 is actually 65% vs 64% :-)

Thanks for sharing your knowledge through these videos. Do you give much validity to the statement that cast iron heads will produce a slightly higher compression ratio through the fact of their ability to retain heat over aluminum heads? It's a given that the aluminum heads may be preferred because of the lighter weight factor that may negate any power increase derived through an iron head's heat retention factor, but can you give an approximate range of compression ratio increase for an iron head over aluminum with the same combustion chamber volume? Thanks for all that you're doing to further the hobby, looking forward to viewing all of your videos as there's so much to learn from them.

Awesome video! Thanks!

Awesome video.

thank you very much for class !

Curious if you have any similar insight on how to select intake runner volume and valve size... Love your videos, very educational, subscribed.

Let's say we are building a small block for a family jet boat. Using factory cast iron heads. Don't need much bottom end for the boat to idle around. Need some decent mid-range to accelerate the boat onto plane and maybe pull up a skier. Need max TQ at 5,000 RPM to maximize the strength of the input to the jet pump as the boat reaches max speed. We have wet exhaust, so we need to stay out of reversion to keep it from sucking water vapor back into the exhaust port at idle and above. Cam will end up being something like 270* at 0.450" lift with an LSA of 112* or so. Installed straight up or maybe 2* retarded to help max upper range power. Can get near 1 HP per CI even with this small a cam and not a ton of carburation : ) This same motor would not be terribly fun on the street, but with a few tweaks, it'd be OK. Advance the cam 4* to help with lower end power and launch and it'll work. This is why there are so many boats getting bought off CL just to flip the Marine Engine. And Marine Cams get used in some street applications.

Man excellent video! I've tried to understand much of this in the past but this really clears confusion! Do you take in work from the locals? I's like increase the flow on my 396 heads. Quick question, is it really expensive to take heads from roughly 68% of flow to 80% or better and is it worth it? I used your excellent tutorial to get an estimate based on my configuration and would like to target a little more HP. Thanks for the the great information.

I really like your detailed videos, keep it up. The coil spring vs compressed height vs pounds of force required seems technically correct but not all springs are compressed at once and once compressed they have potential energy they release when rocker arm fulcrum goes back up. Basically, assisting the next coil springs downward action. Its basically a zero-sum game with the springs with the exception of friction. Thats kind of the purpose of a spring.... storing energy. I think the initial force required to compress the 1st spring is input electrically via the starter. Am I missing something?

Not sure if you're still looking at the comments but here goes.. really awsome presentation! I've watched this several times and will probably continue to do so. My question is on flow percentage. Ls3 head. 823. So the stock cfm numbers aren't bad. Like 312/216 @.600. These numbers are still below 75 percent flow. With the dual profile cam I'm assuming that will increase the flow percentage? To calculate With a dual profile I also assume I would use the lift numbers on int/ex respectively? Also Is there any advantage to porting just the exhaust? To increase the flow percentage? I. I'm building a ly6 block bored to 6.2( saw your video with much interest) lol. Going in a jk jeep. Daily driver-ish and want a solid 400 hp at the wheel. Just cuz! Lol. Also I'm going to run the vvt. If you see this and feel like responding I'd appreciate it. Really liking your channel. Doug

Great video. Made perfect sense. I’m guessing the high-end aftermarket head companies publish their flow numbers then, right?

This is exactly why I don't even try to make that decision, I use a professional like yourself. I actually have a 350 crate engine that I installed in my truck 20 years ago that I'm fixing to put the Holley Sniper on and I really want to replace the heads and the cam at the same time and I won't be making that decision. I'll pay for it but this isn't something that I'm qualified to do. I know what I know and I do those things that I know very well and this isn't one of them. I'm happy that there are people just like you in the world.

Too many ads but brilliantly informative! 👍

I've learned a lot from this video 👍

most folks try to install a cam in the 5000 to 8000 rpm range in a motor that cant rev that high, the other deal is, like on a chevy or ford, if you change rocker ratios from 1.5 to 1.7,on a stock cam and it runs better thats when you look at cam profiles, more lift and durationusing a vacuum gauge will tell you a lot.

Building a Ford small block for the 1st time flat tappet & solid lifters, wanted to ask about the break-in proceedings which seem a little excessive, special oil, special weak break in valve springs, start up and immediately run it at 2500 for 1/2 an hour, starting to make me nervous ! Pretty sure they didn’t do this with new engine’s back at the factory in 1960 whatever, was planning a more gentle approach to this, put some oil in and fast tick over while it warms up for 15 minutes and check everything out, all advice welcome 🙏

Saturation is like friction loss when trying to push large volumes of water long distance through too small diameter of pipe.

WHAT ARE THE FLOW NUMBERS FOR TBI HEADS ? PLEASE THANKS LOVE YOUR VIDEOS

best video ever.

There is probably some math you could apply. Springs have mass and spring rates and you should be able to find the actual mathematical point where the amount of hp gains (at max flow) is perfectly matched to the lowest possible parasitic load from the springs. That would be even better than ball-parking. I bet GM's 420 lift is very close to that perfect point. It might not be the most power that can be made by that engine, but rather the most power with least effort, which should translate into more efficiency and more durability. So in addition to usage type (strip vs street etc) the amount of reliability (endurance) gets to be more of a factor with this move toward a more precise design of the engine. Thanks for moving us all a bit further in that direction.

Go to the cam catalog pick the cam you want. Then buy the cam that is 2-3 sizes smaller and you will probably be close.

thank god for your help. the orgy of cam dyno testing is fun to watch, but virtually, completely unhelpful. You are getting me dialed it :) The one thing throwing me for a curve is, how do I factor in good gas mileage?

Great video but not that much different from the original one. Wahr about compression ratio for the cam selection ?

Ive always said match the parts together. Don't run a huge cam on stock heads or stock exhaust, aim for high volumetric efficiency. With cams in general on stock heads 450 lift to 480 is ideal on performance heads i would say don't exceed 550 or you get reversion unless you have very good flowing exhaust. Also the higher the lift the more energy it takes to open the valve. For a good chop high lift isnt the only way lobe separation angle also changes the cam sound without a huge lift.

Thank you putting this together! The formulas for estimating max potential hp of the heads is great. Do you know of something similar for calculating max potential HP of the bottom end as well? For Example lets say you calc that your heads can support up to 600 hp. However, if the displacement, compression, etc. in the bottom end is not there you wouldn't actually be able to make that 600 hp, right? Thanks again

thank you man.

Any chance you have a formula in your bag of tricks for determining throttle body size?