Anyone here fabbed up an intake for a 5.9L magnum? I have some 3/8" aluminum plate that I want cut out the intake face plates and carb face plate and use some aluminum tubing to create the runners. Just wondering if anyone else has done this or though about doing this before.

This is for my Chrysler Conqueror SIII Jet boat so its a little different setup and they run almost constantly at 3k+ rpms so a nice single plane is what is needed.

On the water crossover thinking of putting in AN fittings since I don't really need a thermostat since it will be running river/lake water through it as cooling. I just think I can build an intake that will best fit my purpose for less than I can buy one for. Plus there is the cool factor that I built that intake. One more thought is that if I can build it then I can easily modify to fit the fuel injection later on. I could also start with the old beer barrel manifold cut off the barrel section and weld up the runners and a new carb top plate.

Anyways what are everyones thoughts?

Thanks
Chris

Don't you want some taper in the runners?

If you look at Hogan's work you'll get the picture.

IMHO it would be much easier to modify the angle of the bolt holes on an LA single plane, that's the only difference.

Or you could hold your nose and buy a Chinese intake for the Mag heads.

If you're thinking fuel injection I suggest you visit friend James at www.bigblockranger.com.

Also keep in mind that intake manifold manufacturers make their prototypes from fiberglass.

R.

I believe I can create the taper when creating the runners.

I could buy an intake off ebay for $170. But I have a bunch of 3/8 Aluminum plate and a friend of a friend I could use his welder. So I just have to create the flanges and buy some material for the runners and fab it up figure will cost me less than $50. And it will be cool cause I made it.

The stock "Beer Barrel" intake is kinda a single plane design with 15.5 inch long runners, taper, and a slight twist to each runner.

The original 1993-1995 design had a center wall that came within 1.5 inches of the bottom, but did not seal the two chambers from each other.

It might of been that the purpose of the center wall originally was to ensure an even division of the exhaust gas recirculation gases at part throttle,
because when they dropped EGR in later years
the centerwall bottom was cut away to create an even bigger opening between the two sides.

The Engine Analyzer 3.2 software says the runners total length of 18 inches "resonate" at 3600 rpm,
And if memory is not playing tricks on me
i think the PipeMax program also calculates about the same rpm.

Placing the resonance halfway between
the 3200 Torque peak and
4000 rpm Horsepower peak
makes sense for a stock pickup engine

I love it! You used one of my secret words..."just".
The quote is:
"So I just have to"
which lights up my board. Long ago I realized that whenever anyone says that word, what it really means is, "Watch out! I'm going to make a very complicated job seem really easy!" I even catch myself doing it and have to stop and think. Most of the time my theory is right.

So, if you really want to do it, go ahead. But if you go way over budget and time before you finish it, if it ever gets finished, I told you so.

It's great when people try something different. I regularly get hosed down for coming up with weird stroker combos, so I can respect the trying. But the goal of doing it for less than $50 is unrealistic.

More than 10 years ago I read this really neat article by a guy who designed and built his own intake for a big Cadillac engine. He had the brilliant idea of increasing the length of the runners to boost low-end torque. Now, why you'd try to boost low end torque on a 500 cubic inch engine is beyond me. But he laid the whole thing out and had the runners crossing under the plenum. The flow path looked like half of a heart shape. The mixture made about a 120 degree turn out of the plenum and I could picture the fuel droplets centrifuging out as the mixture went around the bend. It'd probably work as a dry flow intake, but not so hot with a carb. At the end of the article he had cut all the parts out and "just had to weld them together." I never heard any more about it.

Keep us posted.
R.

The iron V10 manifold design is worth looking at carefully
With a 25 inch total length
that creates two resonances...
One at 1700
and another at 3400 rpm

Seems like the 5.7 Hemi manifold runner was 27 inches
Then had a dual path length upgrade a couple years ago
... Anyone know the current lengths for the low/high runners?

The hard part will be keeping it from warping when you weld it up, and getting it to seal up afterwards. You will have to get it machined flat onall mating surfaces after you're done. That will bump up our $50 estimate considerably.

There's reasons Hogan intakes cost so much.

I do understand the "just gotta do it" thing though.

thanks for the tips. The reason I figure it will cost me less than $50 is because I have almost all the materials already and some of it I would consider as being free since I got them in with other parts/vehicles that were parted out for much more than what I paid for the whole.

I am not planning on some long ram design just a simple straight runner single plane like a torker or M1 without the $300 price tag. If it works even for a while great it worked. I have been looking at the chinese "air gaps" on fleabay for $170 and right now thats not in the budget. It says they are good for 1500-6500 which is the range this motor will be working. The Jet Propulsion kicks in at about 3000 and max rpm will be 5500-6000. It will be living at at 4000 all day long which is more like a drag motor than a street motor. I know to get it above 5000-5500 will need to upgrade the springs and possibly cam but for now stock just want to get it on the water and see what this Jet will do and then work on some upgrades may even do a 408 stroker kit down the road.

This will be to get me by unless it works well enough then will leave it well enough alone.

To keep it from warping was going to mount it on the longblock while fabbing it to that it will stay within spec and planning on doing it in stages to minimize the heat.

I am currently leaning to cutting up my barrel manifold to use for the flanges and just blocking the injector ports possibly with the injectors for now welding on the square tubing and blending it in and at the top forming the tubes together to form a plenum with dividers and welding the carb base flange on there could possibly use a 4 1" adapter plate as well or cut one from my aluminum plate I have.

I have raced a lot in my past and researched a lot of different plenums and intake designs and for what I need this is a basic and simple design. with a few minor touches to make it work well.

More power to ya.

If all else fails the 340 Torker just needs to have its bolt holes changed, everything else is the same.

R.

Yeah if I could get my hands on one. I have a cast iron 4 barrel intake but its real hard to mod the cast iron one. I have been on the hunt for either a used magnum 4 barrel intake or a used LA 4 barrel intake.