That's what I love about this channel. No Bologna and Bs just Facts and Fajitas!!! 🤘

I took apart a factory 318 4 barrel, from the early 80s, and basically found a 360 intake on 318 heads. I didn't have the engine since new, but it looked very original.

Most of your real world performance gain with the four barrel intake comes from the increase in runner and plenum volume and more available carburetor cfm. Most of the factory iron intakes are just so restrictive that any improvement at all makes a tremendous improvement. The street dominator is okay as long as A: the ports aren’t modified at the runner exit. And B when using more cam, gear, and compression. But it still won’t equal an air gap or an LD340 because of overall internal volume with its small window runners. One of the best available 318 manifolds at present is the Weiand stealth. 318 sized ports (same as the action plus, look it up on Holley), but the smaller square bore plenum makes it a near copy of the old Edelbrock LD4B, which also had 318 sized runners after the plenum bell mouths. In fact, the runner layout arrangement is identical, too.

Great video! Great explanation and test! I've ran 340 and 360 4 barrel intakes and always gained power and was told the same restriction story in the past but I always used them anyway. Thanks for sharing this information!

Love your demonstrations. Your Lowbuck 318 tread is why I have a 340 cast iron intake in my inventory with a lot of new unanswered questions

To further illustrate your point, back in the 70s, when aftermarket heads and intakes were less common, it was known that a 351-C 4 bl intake would really wake up a standard 2bl 351-C, despite a HUGE port mismatch; similarly, the hot ticket on an oval port 454 Chevy was to bolt on a rectangle port manifold. Nobody under about 50 would know that.

Love this guy! I'm in the making of converting my 318, intake, carb, and header check complete. Just waiting on warmer weather.

That's good stuff... I learned this about 25 years ago and it's truth! I too had a Street Dominator intake BUT I had it on a 340... What a mistake.. I found a LD340 and it was night and day difference...later once the Air gap came out I swapped again! Lol Andy

It's all about the flow, gasket matching is a definite plus.

I have the spread bore intake with an adapted square bore carb as well I was feeling not great about it because it seemed a little hokey but thank you for sharing about the street dominator!!!!

318willrun throwing out science today! Great episode!

Had a 273 2Bll. added a 340 intake a 500 Holly 2Bll. Inside a 68 340 stick cam and lifters and springs . turned 14.6 all day in the 1/4 mi. and drove home .

Tim i do agree with you, i have also put 4 barrel intakes on a 318 only results was more hp. thanks Tim

Excellent presentation, totally makes sense. Thanks for the education.

Another great common sense video on a topic that most people just don't seem to understand. Keep em comin - great work. Hope you enjoyed your fajitas - they sure looked goooood. Oh, and top up that Pepsi with some rum. Thanks

Good explanation. Totally agree with the logic. If it was a forced air induction or something it might be different, but with it being a vacuum draw that overhang should be negligible. Thanks!

Interesting concept. It’s a complex physics problem, there is no such thing as engine vacuum, it’s just more, or less pressure which causes flow. The cylinder volume is increasing on the down stroke, hence the atmosphere pushes the 14.7psi into the cylinder, P1V1=P2V2. Then, you have compressible flow vs non compressible flow characteristics. Best to run it in FEA fluid software, and check your hypothesis. Older piston pounder aircraft measure the manifold pressure as a function of inches of mercury, hence always a positive pressure value.

Nice!! Back in my younger car guy days (before I even knew about this kinda stuff), I had a strong stock 72 318 in my 67 Dart GT. I found a stock mud/late 70s four barrel intake. Added an old Carter Comp Series 1Kcfm TQ, and it was amazing!! This was the only smallblock ive ever owned that I truly enjoyed!!

340/360 intake on 318 ? Absolutely!! Been doing it for years! You keep schooling’m, “Will” 👍👍

Right on the money!!

Great content and uploads.

X WHEN I TURNED 18 RUSS WAS A MEMBER OF BIKINI STATE TRUCKERS AND IT WAS HIS MISSION TO TEACH ME SOME FINER SHIFTING TECHNIQUES. THE VEHICLE OF CHOICE WAS HIS 73 - 74 DODGE STEP SIDE WITH 318 IMPROVED WITH SOME 340 STUFF, 4BBL, HURST ON THE FLOOR, GLASSPACKS ON DUAL SIDE PIPES. DO NOT KNOW ALL THE TECH STUFF, BUT HAD THE TIME OF MY LIFE IN 1981, HANGING OUT DOING THE GUY THING SAFELY. NEVER FORGET RUSS ALL THI TIME!

at higher rpm vacuum drops. and street engines make way more at lower rpm's. it's about velocity and that easier gulp at the valve when it opens. but i agree with your point.

I totally see your point & agree with it. You see, im a ford guy. I like to mudrun. So I use BBF. It is common for on the BBF to use a cobra jet intake with its oversize ports even on non cobra jet heads with the mismatch ports & get gains from that combo.

I had a 1973 Roadrunner with a 318 and factory dual exhaust. At 20,000 miles, I took a four barrel manifold off a 1970 340 Duster, installed a Direct Connection Purple Shaft cam, 550 cfm Holley and headers. I had that Roadrunner for 18 years and the difference in power after the modifications was spectacular for what it was! I ran that car at York US 30 Dragway and Maple Grove dragway and would run high 14's/low 15's all day long! Sometimes I would strip the car for weight and add a set of slicks. It was a lot of fun! Bill from Linglestown, Pennsylvania

I put a 4 barrel carb and intake on a 74 roadrunner that came with a 2 barrel, still ran fine.

Will be doing this in the spring with a 72 340 intake and a thermo quad

Solid advice

Great video

Thanks Boss..

Awesome job! Iv been saying that for years and got alot of disagreement lol

My power wagon has a 318 with 340 cam, long tube headers and a 360 intake. Runs strong! And sounds nasty! But the 600 Carter is a bit worn out, upgrading to a Holly 750. This was a great video, I've been trying to tell people that its fine to put a 360 intake on a 318 for years, only time it would be necessary to port match with this setup is if you go forced induction.

Cool video!

The "Performer 318/360" is the manifold to buy. It has the actual name I put in quotes. If you look at the runners, they are large, right up to the very end where they taper down to 318 size. This enables you to run it on 318 heads. For a 360, you can leave it like that or grind the ends open to 340/ 360 size. And contrary to what is claimed, I have seen port mismatch with a 360 intake on 318 head engine, especially around the exhaust crossover.

Yep!

I put a 340 cast intake on my 76 dodge coronet 318 2 barrel and it was a gain. It performs well. I’m not having as much luck with my street demon carburetor though lol.

Excellent video. Well done. I'd like to add, I'm sure there is a negative impact of the ledge of the port. The question is, how much? Answer: Not enough to make a difference.

I see a vacuum. . .I see two different size ports. . I knew what was coming!!

Good demonstration. I did some flowbench work years ago when doing alot of carb work, and the amount of increase accomplished by port matching or even for that matter porting is minimal. But that said tubulence does affect charge somewhat. Uniform flow is helpful.

You're better than zquil! 2 minutes in and I'm ready to sleep.

A couple of things .... Air in the intake flows much faster then your vacuum cleaner and it has fuel which has mass ..... Having said that on the dyno sometimes we go back and cut an edge to excite the fuel and mix it better and the mismatch will do the same thing and though the turbulence does drop the cfm flow a bit it can be more than offset with a better quality mix and the stopping of fuel dropout mostly in lower rpm and mid range rpm... If the mismatch is big enough and a large runner your thinking is actually correct but what happens is the intake runner becomes more like plenum space and the engine sees the head port as the only runner and it acts like a shorter runner working better at high rpm .... Just thought I would try quickly to help you understand why and how what you have seen works

I raced 273 Hi Po's, 318 poly, 340's and 360s back in the early 70's. My brother and I tried just about everything. My 71 Duster 340 Super Stocker ran 11.50's @ 122mph. We even tested a 340 Torker vs a LD340. The LD 340 was 2 tenths better. Had a Tarantula too and that really sucked!! (Actually it didn't suck very well!)😂

Subbed👍 Im not a performance guy by any means. I enjoy reading your posts on fabo. By the way, now you tell me. I stuck a 69 340 intake on my 83? 318. That 318 is a factory replacement engine. Like a crate engine from the 80’s.

I had a 1969 Sattallite with 318. Stock cam, headers, dual cheap turbo mufflers, direct connection electronic distributor kit, my buddies throw away cast iron 340 4 barrel intake, holley 600 1850. Believe the 69 318 had the good compression. She had enough pep to stay fender to fender with the new 80s Muscle cars.

What I do is port match the 318 heads to the 340/60 intake just take the 360 intake gasket and paint the area that needs to be cut out get a die grinder and open up the 318 ports

Putting a TR5 Edelbrock tunnel ram intake on my close to stock 318. Going to use a pair of 500 CFM AVS2 Edelbrock carburetors on top. I plan on using progressive linkage because I have an open plenum and I think that I can get some decent fuel mileage with this setup. Using 302 quench heads on .030 block. Not sure on the cam yet. The TR5 is 340-360 size runners. I was thinking about porting the heads a bit by reducing the pushrod bump in the intake port and maybe raise the port a bit to match the intake height.

Chrysler used a 360 manifold on the 4bbl 318’s from the factory. I put a 360 4bbl on a 318 multiple times and it works. Is it ideal? Probably not, but it works

I bought an LDr2D2C3POballbearingdrive intake for my Kanutsen KMG635 motor.

Excellent

On the money .

Im running a 318 poly engine with a weiand 4 barrel intake and the 4 outer ports are cast about 1/8" bigger on 1 side of the port which creates a shelf for the fuel to pool on so those 4 ports run a little richer

I put a 340 torquer intake on my 76 318 factory heads and it runs pretty darn good. But i would like to put some 340/360 edelbrock heads which has a bigger intake valve and exhaust valve. The biggest gain that i got was doing the total timing on that 318 at about 32 degrees. On the torquer 4 barrel intake i have 500 CFM after market Holly 2 barrel. With an adapter that goes from 4 barrel to 2 barrel for right now. But in the future it will have edelbrock heads and a 750 holly carburetor. Anyway i see your point. It does not make a difference in air flow if you put a 340/360 intake on a factory 2 barrel head, at least not enough to make a difference.

I also try to explain to people that you can't use 340 or 360 manifolds on a 273 or 318 because ports on the 340/360 ports are different sizes and will cause exhaust leaks / burn outs even though they bolt up the same . if your going to use any header that all have the 340/360 ports they need to weld up the ports to match the smaller ports and use fel pro manifold gaskets for 273/318 instead of the typical 340/360 port header gaskets. Now if you switch from a 318 2 barrel intake to a 318 4 barrel intake with 318 ports that works also

I put a LD340 on my 318. It worked fine

I'm running a 360 performer on my 318 roller cam in my 87 ramcharger never gave those forum people a thought! The thing runs great and gets 15mpg....plan to run an offenhauser 4 bbl on my other roller cam 318 in my 72 dart and yeah the forum people are left out of that one too! Lol 😆 go with what you know works not hear say!

I know this is an old video but... In the late 80's and 90's when we were young if we had a 318 car we put junkyard factory 360 4bbl intakes,LD 340 intakes or whatever we could get cheap..It resulted in better performance and car was noticeably a lot quicker,you really noticed it! We always did duel exhaust usually first as it sounded better lol,then went for power with the 4bbl after a few more paychecks as kids at 16 years old etc..I always told people slap a 4bbl on that 318(or any 2bbl 360,383,400 even one buddies did a rare 1964 361 Fury )! Even with the 2bbl the duel exhaust had a feel in the pants performance gain,slightly but you felt it,at least it sounded like it :) My uncle put a 4bbl on his new 1985 Fifth Avenue,got rid of the lean burn and added a 4bbl,made that car what it should have been,peppy and actually quick luxury car! Dealer added and gave the factory warranty,that he never needed.. **FYI: Nice demonstration!

‘An influence’

I never really thought about this. But now that you bring it up I have questions and headaches! 0pening the port to “match” would be considered “bellmouthing” Does this help? I have images of velocity stacks and molded clay on heads on flowbenches. Bring me th Tylenol.

Well he settled it for me now to pull a 360 intake off a junk yard pickup for my 80 cordoba

Good video. I think or hope at least folks r saying it would be better to have larger heads. but to say simply a 4bbl and a 340/360 intake on 318 heads is ineffective is stupid.

I want to know what the setup is on the gray van doing the burnout in your intro.

You can't compare the dynamics of water to air! Water doesn't compress and air does. Lot's of other factors too.

In the interest of science I put a 68 340 intake on a stock 74 318 with an AFB. Lots of guys say thats a bad combination, it worked very well. Also in the interest of science I tried an old Edelbrock SP2P, lots of guys say those are junk. Well in that case they were right, power and gas mileage went down, even low end power. On paper that SP2P should've been the better of the two on the pickup. But I don't drive on paper. 😂

You're right and its common sense that with vacuum it's not going to hit the edge and bounce off and really if u only gasket match the edge of the port without doing the whole port its not going to help nothing because you're only moving the bottle neck in a inch then you still have the same size port but you can put bigger ports over small ones and never lose anything, only good gains and burning rubber to be expected out of a better intake because it will be able to breathe better, Im like u i don't understand why ppl get so confused over this 🤦‍♂️🚙💨💨💨💨💨💨

If the ports don't match, you will always get a stumble.. And yes you will get more flow, just not the max.

Sorry! Was trying to send this link to latest Charles Servedio’s mission impossible 318 project video and the message to there got copied and pasted to this, lol!

Why not just gasket match the port entry at the head? Or, why not just put some JB weld in the intake to reduce the size of its exit window? My question is why do guys go to the trouble to gasket match everything else. The garden hose effect isn’t going to spray water back at you. But air is lazy. Water is a decent analog, but it doesn’t have the same mass as air, and has more force behind it once on motion. When air is in motion it doesn’t have as much force as water. It’s more easily disrupted when it comes to flow. Vacuum does draw in the air fuel mixture to some degree, but in a tuned engine, when the exhaust is tuned to the same rpm as the intake, you have force behind the air fuel mixture, it isn’t just drawn in by the vacuum of the piston moving down in the cylinder. Sure, putting a larger intake on a 318 will aid in flow. And it will flow better than it did with a restrictive intake. But you are losing potential, and your losing a lot of potential when everything else is properly tuned to a specific RPM band. Think of the t7ned airflow this way, and the I’ll get back to the port mismatch situation. It all starts with the exhaust stroke. Ok, that sounds kind of backwards, but trust me, when the engine first fire up the exhaust tuning begins. When the cylinder fires on thr power stroke it generates pressure in the cylinder, then the exhaust stroke begins with the opening of the exhaust valve, and a positive pressure pulse or wave travels down the primary tube of the exhaust, to the collector and put to the open atmosphere, where it collapses. The positive pressure wave or pulse travels at somewhere between 1100 and 1400 feet per second. When it collapses into the atmosphere as it hits the outside air a equally powerful but negative pulse travels back up the exhaust pipe to the a cylinder, and when it’s times or tuned correctly it reaches the cylinder just as the intake cycle begins and the valves are both open during the overlap phase of the cam. The negative pressure wave runs all the way out through the intake into the p,enum chamber and out into the atmosphere, but as it does it begins to draw in the air fuel mixture. Any interruption to that negative pressure wave and it loses strength, it doesn’t cease to exist,so it will be an improvement over a restricted intake tract, or improperly tuned set of manifolds. This is kind of lie free supercharging. To maximize its effect on hoe the engine makes horsepower all restrictions should be removed and the intake and exhaust must be tuned to the same rpm along with the camshafts timing. Remember, it the piston is the heart of the engine, the camshaft is the brain! So that’s why it’s important to match the port windows on the intake and cylinder head. The same is true for the exhaust port and header. A smooth properly sized port window must be matched to allow that side to work properly. A disruption on either side costs the horsepower you are trying to create! I hope this helps. I hope tha now you understand where this comes from. Does it matter on a low power street engine! Why I the world would anybody want a low power street engine in the first place?!?

Question I put a 1985 318 engine in my Duster but I had to change the Distributor with the vaccum advance but the carburetor is setup with a lean Burn system. Will I have to change the carburetor out?

Stock 318 , mild cam ,intake,carb ,headers will wake it up

I´m swapping my 318 2bbl intake manifold for a cast iron duster 340 intake manifold and a 4 bbl carter avs carb, any further advise?? , thank u!

Question I have a stock 340 as I know what could give me more horsepower and what do I have to purchase to get that

Please read.i have a 79 chrysler cordoba (for parts) has a factory 318 hp 4bbl. H code on vin the 4bbl is a 360 intake.if chrysler does this from factory u will have no problem .the only thing i would do as i did on my 79 dodge magnum is gasket match port the 318 head ( intake side) to the intake.i have done this and works well.the problem u would have is trying to put a larger CFM carb than engine could handle.a holly 600 works well on a factory speck 318 (135 hp) with factory intake.

I had a '72 Dodge Polara with 318, it had small ports, My Dad's'86 truck had 318 but it had big ports? High swirl head on the '86?

if putting a 4bbl intake on a 318 head made less hp than the 2bbl, people wouldnt be doing it :) people try to say the same thing about the huge pushrod bulge on magnum heads, yet they flow so fast and good.

I’m literally running the old TM5 single plane intake on my 318 with 360 heads. Why? Because if it fits it ships lol

I had put a Edelbrock 360 4brl intake on 318 heads once. It did improve the performance, but once I changed the heads for 340/360 sized ports, the improvement was greater. I isn't a loss of performance, it is a lower gain of performance to go from 2brl 318 intake on 318 port heads to 340/360 4brl port intake on 318 port heads. Once the ports match up, the gain is increased. However, you may likely lose some compression if the 340/360 heads have bigger chambers. (I had my 360 heads shaved and used the thinnest head gasket I could find to offset some compression loss)

So kinda an unrelated but related question just because yall have alot of knowledge.. can you put a TR5 edelbrock tunnel ram onna AMC 360?

What would be your opinion of an edelbrock 500 cfm/ #2147 intake. For my 318 2bbl conversion.

I’ve used 340 intake on a 318 and it ran great. Definitely use 340 gasket or you will have a nasty vacuum leak.

As someone who has owned many different old mopars across the years,a 318 will benefit going from a 2 barrel to a 4barrel. The port mismatch will really not matter. You can make anything work with mismatched parts as long as they bolt in and operate.People need to use their brains and THINK about what it is they're trying to achieve. You can bolt 340/360 heads on a 318 block and it will run even though 340/360 heads have larger combustion chambers and it creates a drop in compression ratio.It boils down to what you want and what do you expect from a given combination.

That all makes sense, but what happens when you put a 318 intake on a 360? I want to buy the Edelbrock Performer for my 360 (mainly for weight savings), but the ports are 318 sized.

I'm running two roller cammed TBI 318s one in my 87 Ramcharger 4x4 5800lbs monster with a preformer intake and AFB carb 600cfm gets 13mpg around town 15 long runs and makes decent power going to run the other roller cam in my 72 dart with an offenhauser AFB carb and dual exhaust and much lighter than the ramcharger! you think results will be even better Damn right they'll be!😂👍 and if they are so worried about the mismatch then get the die grinder out and grind me a pound!

It's my understanding the step should be in the opposite direction of flow and near the bottom of the port to help get more fuel to atomize. BUT, that ain't got nothin' to do with a stock to 500hp engine. 🤣 I'd think it would be more important on the exhaust to help prevent reversion. Yet again, Dulcich smashed those headers to smithers on engine masters and it had LITTLE effect on power so.......... 🤷‍♂️

You failed to discuss how the gasket fits. I however agree with your last statement about machining the smaller port to match the larger one. Your demonstration with the vacuum and the strip of paper is not a very good one because it’s not a sealed chamber (sealed like an assembled engine). Using a large ported in-take on small ported heads would for sure have some drag/turbulence but if it makes a huge difference? I don’t know how much without some real data for comparison.

I believe you but just for discussion sake I have a few questions... 1. In your Street Dom to dual plane comparison, was the 318 a mild build, stock converter with highway gears? If it was then I would choose the dual plane too. 2. If you ran a 318 w/ 340 iron intake and let’s say a 340 cam on a dyno or drag strip, and then port matched the 318 heads (about an inch deep?), are you saying there would be no hp or torque difference, the power curves would look the same? 3. Just for the heck of it, what if you had a 318 with 340 cam, 340 heads and a 340 dual plane intake, but you had a steel shim intake gasket with 318 sized port openings, ran it on a dyno or drag strip, what then? Not sure how much, but I think there would be a measurable difference.

Heads is the best thing you can do!

I got a 318 with a slight cam, Edelbrock LD4B intake with a Carter AFB 4 barrel with the 302 swirl port closed chamber heads. Would I have better luck in performance with the heads I have now or 360 heads??

Correct the thumbnail title please.

Getting ready to put a air gap intake on my 318 should I use 318 or 360 intake gaskets?

A friend had a stock 77' Volare in 1980, not a lean burn. Installed a 360 2bbl manifold and 500 cfm carb. Grinded the 318 heads to gasket match the 360 manifold. He recurved the distributor with 383 parts. His 318 ran strong! In the 1973 oil crisis Chrysler should have paid attention to the 318. Or Chrysler should have used the 360 bore of 4.0 inch in the 318 block for a 332 cubic inch. The debate 2 bbl vs 4 bbl some applications 2 bbl carbs work good. I think Outlaw sprint cars run 2 bbl carbs. Keep those 318's running.

Whats your opinion about port matching intake to head? Is it worth it?

Can you imagine if you experienced a time in your life where you got a clue

Look up cowanda effect.

All & any interfearance has to be blend & matched for top flow. All & every stock motor ford-gm- dodge , are never matched . & Your vacuum demonstration has littel or no velocity , now add air speed to that edge , not . Sure there's gains👍! Nothing compared to matched /even connections performance. You have a good point as far as bolt on & go 😊👍 it's same as production lines. ""But why not take few min,& blend & remove the blockage , for the huge top end gains 😊 after all , it's the main reason one is grabbing the 4brl intake to start 🏁🥂🏁 so 50&60s basic fundamentals 🏁

Will it run .Yes is it Correct .No

Victor 340 is 318 sized. which is ironic

Put the 340/360 intake on a 318. Then add 360 heads too. Ports match, flow increased, this discussion made irrelevant. Causes new discussion: chamber size vs. compression ratio. (Edit): Don't put 360 heads on a 273 though, bore is too small.

It may be a truth though it's not necessarily a fact.

Your dead wrong because I have 360 heads on my 318 and I'm running a holly 650 and it runs like a stripped as ape

This is Weird just put some 360 heads on it problem solved