Dividing the Siamese Intake Ports in a factory GM 250/292 Head. 9 to 12 Port mod. EP.20

9 port to 12 port modification with multi-port fuel injection on my 292 straight 6.

[@NMX777]

I really like this project. I hope it ends up performing well. I'm hoping it significantly increases low and mid range performance. It would certainly enhance the 292's already respectable low end torque.

[@95Z28A4]

WOW! And to think I was searching for TBI conversion information when I found your channel.

[@SquaredAwayGarage]

TBI can easily be done with a Sniper if you want to go that route. Holley had a hyperspark distribution for the GM I6s now.

[@matiasdamian8106]

Great job dude! i Really appreciate all the effort you made into this engine, im from Argentina, we have Thousands of chevy's inline 194, 230, and 250's from the chevy II cars, and besides that, you ONLY see this kind of work on 1/4 mile really high prep engines... Nothing like this on streets cars... Same happend with the MPFI, only see that kind of things on race build engines, Brazil people really did upgrades to the chevy 6 platform, they actually made a STOCK individual port head, here we buy many parts from brazil. I did not know actually there was a Manual made from all the chevy 6 family, that made me happy. Anyways, I would love to keep watching content like these brother, i see V8 everywhere everytime, not many people like you make this stuff... Keep the good work buddy!

[@SquaredAwayGarage]

Thank you Matias! I'm glad you liked it. I'd like to get my hands on some of those Barzilian parts, but what I have is working pretty well.

[@matiasdamian8106]

@@SquaredAwayGarage For sure what you been doing is really good! I mean, taking in mind that you used the original head in terms of the siaemese ports, and didn't have an individual port to start with, the job you made is the best I could imagine to efficiently split the ports. So, again, great job. Oh, and i was wrong about the origin of that aftermarket aluminum indivual port head, it actually was made by "Kirby-Sissel", it's known as the "Sissel head" and it's a USA made head, not brazilian. A youtube channel called "Mark Stirnemann" he explained the history of that head, basically was in the market many years ago, but the company passed to a guy that's not casting that type of head anymore... So it only remains the ones that were made before

[@SquaredAwayGarage]

@Matias Damian I'm familiar with the Sissel head! Looked for one when I was dreaming up this engine build. At the time, I thought they were a bit too pricey. After everything I've done though, it would ha e been worth the cost.

[@matiasdamian8106]

​@@SquaredAwayGarage Oh for sure i mean, any custom work, the time that you spent, not even mentioning build custom parts, with time all that surely it'll be a high cost, but if at the time you looked for that head you couldn't afford it, it's what it is right? we do the best we can with the things we have, that's what u did, what i did, and what many people does but, at this point, i tell you I really admire what you built, its awesome to see all the effort worth it! Looking up for your futures videos dude!

[@carlosmarrasca]

@@matiasdamian8106 ​Brazil have a stock individual port head. It was developed by GM for the Chevrolet Omega 4.1

[@johnnypenhale5743]

Nice work keep it coming

[@SquaredAwayGarage]

More to come!

[@mattjohnson3050]

Great work, thank you. I'm hoping to do some of this not sure I want to go as far as you are

[@SquaredAwayGarage]

There is a lot of work here. Just be patient and take it one step at a time.

[@heathhenderson7217]

Amazing work 👍

[@SquaredAwayGarage]

Thank you.

[@joe-hp4nk]

The first thing I would have done is put two carburetors, one on each side of the center inlet to equal the distance to all cylinders.

[@jeanrigo258]

Great job!

[@truthboomertruthbomber5125]

I wonder if you could section some 181 / 3L marine heads and then furnace braze them together to create a 12 port 6 cyl head ?

[@SquaredAwayGarage]

Similar things have been done successfully. Have you heard of this being done with small block heads?

[@truthboomertruthbomber5125]

@@SquaredAwayGarage I would think the head bolt locations would be same on the 181. The V8 heads are totally different. I had a 153 from a mail jeep at one time. I removed the head just to see how close the V8 head was. It's not even close and the water passages are also totally mismatched. The 153 were used extensively in midgets and there were [are ?] custom aluminum heads available.

[@lazyhoundracing9621]

I'm using a Ryan Falconer V-12 head on my 292.

[@2strokepipes471]

The problem with efi on these without the dividers is the charge robbing with the Siamese intake port. Now the problem is the port is very small. TBI is what I kept landing on when designing mine, unfortunately I sold the project before finishing it.

[@SquaredAwayGarage]

Yes but also keep in mind that with the siamese port there was so much volume that the air just lumbered into the valve. Now with the smaller intake ports there is more velocity. The piston is still going to demand the same volume of air as it moves down in the cylinder. Now there is a better air/fuel mixture and charge. At least that is the theory! Think of a garden hose with water running out. If you pick up the hose the water comes out the end and falls somewhere right in front of you. Now put your thumb over half of the opening at the end of the hose. The water shoots out 10 feet in front of you.

[@2strokepipes471]

Yes the velocity increased but does the amount of air your moving increase? By squeezing down a tube it increases the velocity like you mentioned, but it lowers the pressure. Also, due to the increased heat from the same side exhaust manifold, the air density is already much lower than ideal. I am not trying to argue, but there is definitely more to gas dynamics and what’s going on than we are even scratching. Easiest would be to do a back to back dyno test. Tom Lowe, if I’m not mistaken, has done a divided intake as well.

[@SquaredAwayGarage]

@2 stroke pipes I think you're mistaken about velocity lowering the pressure. I expect that pressure will go up. Think about it for a min. The piston going down is still trying to draw the same about of air as it did before. Now the intake is half the size for each valve. Velocity and pressure (vacuum) go up. Better fuel/air mixture, more efficient burn. Tom has chimed in on this build more then once. What he did in the past doesn't compare to this very well. He has tried to compare my build to his a couple of times and has made inaccurate comments and assumptions. Two years ago he didn't think the MPFI was going to work at all.

[@2strokepipes471]

@@SquaredAwayGarage look up Bernoulli’s principle. I’m not trying to undermine what you are doing. It’s cool 👍🏻

[@SquaredAwayGarage]

@2 stroke pipes you may be onto something about pressure according to this, but i think this statement also says a lot. "When a force acts over an area, it is called pressure. A HIGH PRESSURE WILL PUSH FLUID TOWARDS A LOWER PRESSURE. If a fluid changes speed, it will be matched by a change in pressure. In one sentence: Bernoulli's principle says that as the speed of a fluid increases, pressure decreases."

[@travisbooth7106]

I use to have intake that had been done like that and engine had lump ports it came off a asphalt late model from the late 80s

[@SquaredAwayGarage]

Any idea who modified it?

[@travisbooth7106]

It also had what looked like a pyramid in the bottom of the plenium

[@maximilianogonzalez1002]

Hello friend, your project is very good! excellent work! Will you have the plans on how to make the intake parts? I have a Chevy Nova with an inline 6 250 engine and a Fitech 30003 injection system. I have the idea of ​​changing the system and doing it with 1 injector for each cylinder. greetings from Argentina

[@SquaredAwayGarage]

Hello. I sell kits with the intake blocks and fuel rail. As of right now (17Jun24), i have exactly one kit left. All the rest have sold, two of them to someone in Argentina! Email me (email address is at the end of my video) if you'd like to talk more about it.

[@maximilianogonzalez1002]

Thank you, I sent you an email,👍🏻

[@SquaredAwayGarage]

@@maximilianogonzalez1002 I don't see anything from you.

[@samamorgan]

Question: Instead of using the extenders for the injector bosses, why not just mill bosses into the intake itself? It looks like there are spots on that intake at the perfect angle to mill in the bosses.

[@SquaredAwayGarage]

Because the throttle body and the fuel rail need to occupy the same space if you try to use the area cast into the manifolds for the injectors. One exception to that might be the AussieSpeed intake because it has extended intake runner and sets further out from the engine. My assumption is that all the other intakes were designed before modern fuel injection came along. I think they are more set up for an old mechanical fuel injection system. The mechanical stuff didn't have a conventional fuel rail and the injectors where different. Long story short, when I started laying out the efi on my 292 I quickly realized more space was required. And that led to the VERY improved way of mounting the intake.

[@Killah68]

Not if you just use an elbow and mount an Ls holley style throttle body which could be a nice addition for a guy looking to turbo one

[@mattjohnson3050]

Do you feel you will gain much from all that work to divide. Could you angle the injectors to point more to 1 cylinder or would you have interference at the top of the injectors

[@SquaredAwayGarage]

The improvement going to the efi alone was a nice jump in performance. I gained a lot of control over the fuel system, obviously. The folks that have been doing this longer than me think I should see another big improvement. The current expectation is 20 ish ft lbs and 10 hp without even changing the tune. Only time will tell.

[@johnrebus1641]

Excellent work but isn't the injector angle to steep - it will be pointing at the lumps & not the intake valve.

[@SquaredAwayGarage]

It probably isn't perfect, but the injector is also a couple of inches behind the valve. The angle that would be required to shoot directly at the valve would be extreme. In either case I can tell you that the angle I have on my engine works well.

[@troyo4121]

Hi I looked on ebay and I haven't found the listing . Could you send me the listing or the title I'm vary interested in buy a set . I really like your videos and your work you do . Thank you for responding to my first question.

[@SquaredAwayGarage]

www.ebay.com/itm/155129709115?hash=item241e73823b:g:7k4AAOSwKLVi6uFS&amdata=enc%3AAQAIAAAA0IAnkiJekoEaZq0F5HVg73KbeebwAAL7pWqf%2B2QNXhUd%2BaIAG7YdtB5%2BIkdSEI2Gb8GkH112vyK69vJMbPMfINNUReiV24WzZVSx1NjBFGZ2Q50Z7Kn%2F%2BoQVGIBFFJyAussFtJJCfoYTvQDMNifFIwZbocWGOQckwA%2BGz8VEa61dMaiYW5NVzwJvs3U7oheUtRggBfJpiEAwfM%2Bn%2Fgq%2FKVhL6hKcKXcXLPdsix4QPDHZx95HRKjqvTXtiHdjokxtEAPjZ8dYH3oWrk8ZsNeBm2A%3D%7Ctkp%3ABk9SR-TBmv_BYg

[@SquaredAwayGarage]

They cost a little more on ebay of course (fees!). And just want to make sure you want the carb style. Is that correct? If you want to buy the direct and skip ebay, give me your email address and I'll contact you that way.

[@troyo4121]

What's the best way to purchase your intake adapters

[@SquaredAwayGarage]

Morning Troy. If you're wanting them for a carb application they are available on ebay. If you are interested in the fuel injected version, we'll have to trade emails and do a PayPal transaction.

[@toddlawheed561]

Can you buy the dividers or do you have to make them ?

[@SquaredAwayGarage]

You can buy the spacers, but the dividers have to be made. The way they used to clean out the ports pretty much means each head/port is going to be unique. So each divider will have to be to fit your specific head/port. I doubt you'll ever find two that are identical. At least I didn't across 4 heads. They aren't radically different, just different enough that it would be impossible to sell a divider that will work for the masses.

[@TheJohndeere466]

I dont have a gm inline 6 but Im working on a john deere 6 cyl that has real similar manifold and head. I was thinking of dividing the intake port. Does it make it run better or did you do it for installing the fuel injection.?

[@SquaredAwayGarage]

So the issue with siamese intake ports is known as "Fuel Charge Robbing." You can google that and find a very detailed write-up about it. What I did definitely made a difference in my I6, and i assume it would have similar effects on any engine with siamese ports. Aside from actually going through the process of dividing the intake, tuning was my big challenge. I worked with 3 tuners before I found one that wasn't intimidated by the build. Which was crazy to me. So before you begin the process of mechanical modification, you should make sure you can find someone to tune your ecu.

[@TheJohndeere466]

@@SquaredAwayGarage This is a diesel so it has no ecu. Also there is no fuel going through the intake manifold.

[@TheJohndeere466]

@@SquaredAwayGarage THis tractor has similar ports to yours but it makes about 1200 hp and 2500 ftbs torque with a turbo.

[@SquaredAwayGarage]

If there is no fuel coming into the head through the intake, then this modification will not help you. I'm not a diesel guy, but sounds like you have a direct injection system. Correct?

[@TheJohndeere466]

@@SquaredAwayGarage yes direct injection

[@jamesford2942]

Would it be possible that once your inner divider is set in place it could be welded to the lump halves make a one piece unit for each port? I like the idea of separating the ports along with getting the bolt boss out of it in the first place. I also like the mounting flange modification to the intake. It would lend itself to using the individual port extension and putting individual side draft stack injection on it.

[@SquaredAwayGarage]

I did exactly what you are describing. My divider and the 2 pieces of the lumps are welded together to make 1 permanent assembly.