Open Plane Intake

[Sharecropper]

My '84 M1028 does not have the open plane intake (see photo). Was the open plane intake a later refinement? Would it help my horsepower to change the current intake to an open plane intake?
Thanks.

 

[raiburn]

The pic is exactly what my '86 '28 looks like.
I call this "dual plane plenum".

 

[gimpyrobb]

If you are worried about it. I have new in the box intakes with the "open plane" for $50.

6.2 intake manifolds - Steel Soldiers::Military Vehicles Supersite

 

[Mudstone]

i have one of those on my truck. thanks rob.

 

[ralbelt]

I installed one of Gimpy's open plane intakes on my 1986 6.2 runs a little stronger, and looks good as it's brand new,put a few coats of clear on to hopfully stay clean.

 

[gimpyrobb]

Believe it or not, your the first person I have heard from that has one installed! Glad it work well for you.

 

[rebel_raider]

Didn't know they made a intake like that. I thought they all had the divider in them. Learn something new every day.

 

[jimmy-90]

Hey gimpyrobb are those HMMWV manifolds or are they for the later year serpentine belt civi 6.2s??? Also sharecropper if you decide to change to a single plane manifold there might be some issues with getting it to sit all the way down on top of the motor. you might have to saw a little or notch the thing...though im not 100% sure but the civi manifold might be a direct fit with no mods. Anyhow what ever manifold you put on it porting and polishing it will probly give you the biggest performance boost. Just lay the gasket over the head and then the manifold and make the holes in the manifold match the gasket.

 

[slash79]

do the older duel plane intakes like the one pictured have the chevy firing order stamped on them? The intakes on all our 6.5s have the firin g order stamped, thought it was a little wierd.

 

[Armada]

The open plane intakes are good for about 20 hp over the civilian intakes. Back 15 years or so ago when that era civilian truck was more abundant, you could get a good price for a GI manifold. Of course, the GI manifolds were harder to get back then too. Man, I'm getting old...

 

[ralbelt]

There is a tapped tab on the right rear cyl tube that has to be removed to clear the vac pump.

 

[Cucvnut]

What's the HP gain in switching to one of these intakes over a older style ?

 

[T_F_E]

Better throttle responce and low end torque usually

 

[gimpyrobb]

Jimmy-90, I have no clue what these were originally intended for. I google searched the number on the tag and it came back they were for the 6.2. Thats all I know. I saw used ones on ebay for $300, so I figured I'd set my prices a little better. I try not to steal from people when I sell my crap.

 

[Tanner]

My '89 civilian J-code 6.2 has the open plenum intake from factory...

'Tanner'

 

[Sharecropper]

Hey Gimp - I'll take one of those intakes. Give me a holler next time you come this way.

 

[gimpyrobb]

Is Paris anywhere near Winchester? I'll be taking some of the intakes down that way sometime soon.

 

[Sharecropper]

Hey Gimp - Wasn't it you that came by with Bill a few weeks ago?

 

[gimpyrobb]

UH, um, I don't remember the last time I was down. I don't think so, but things have been busy for me lately. I might have and don't remember!

 

[SmokeyDod]

The open type intakes were made for the HUMVEE engines specificlly. There are designed much lower profile so the the hood on vechicle will close. As to HP, I don't think that this designe would add much HP as ONLY "AIR" goes through this (NOT FUEL). It might help a little to smooth up the intake ports but should help more on the "exhaust" ports.

Remember as to HP, you can take off this alum intake , divided or open type and STILL CRANK & RUN the engine. It would run good of course but will still run. So here again the intake design is mainly the lower profile to clear hood space on the Humvees. I could be wrong--just my guess.