4bbl intake comparo

[9.3x62]

So..., couple of questions on intakes. I know an Eddy performer will out flow an oem 4bbl intake, but just how drastic is the difference??
I ask cuz I can snag an oem way cheaper and easier off of ebay than an Eddy.
Also, is there a performance difference between an intake off a Jeep 360 vs a Javelin 360, besides the matter of square bore/spread bore?
Thanks, dudes.

[Stuka]

My Cherokee came with a 4v 360 from the factory which used an MC 4350 carb (750cfm spread bore). When I swapped to a performer intake (which required swapping carbs too, so went with a Edelbrock 1406 (600cfm)) it was a gigantic difference.

Note yes, some of that was due to the carb most likely. Though the 4350 worked well and was recently rebuilt. The 4350 uses a unique bolt pattern that only works with 4350’s, and is not compatible with a square bore intake.

Is worth noting some AMC V8’s came with the MC 4300. Which is a square bore carb and intake. This one is more compatible with other carbs.

I live in a mountainous area. And in some hills I no longer needed to be full throttle to climb them.

For me, it was a fantastic mod to do.

[tgreese]

JMO - if your standard is an aftermarket 600 CFM 'performance' carburetor, no way a factory 4350 is 25% larger (750CFM). Typically factory carburetors are intentionally undersized, for better fuel control under all conditions. Fuel economy has always been a thing, even in the days of cheap gas.

Again my opinion, the "CFM" ratings from the speed equipment companies are a marketing tool, nothing more. Allows some comparison across the line by consumers, and possibly between competing products.

As far as I know, the engines put into Jeeps were identical to what went into the AMC cars. If anything, the full-sized Jeeps would have been more powerful than the cars, since the emissions standards for vehicles of 6000 GVWR or higher were less stringent than for the cars. Maybe a Javelin with a performance package had a superior manifold, but it seems unlikely. Hotter cam, bigger carburetor, higher compression maybe, but I don't see much reason to downgrade a cast iron manifold from the passenger cars for Jeep use.

[9.3x62]

Thanks, guys.
Stuka, your old Cherokee still had the oem cam, right? Your report based on a simple carb/intake swap is encouraging. I have one of those Summit Racing 600 cfm 4bbl carbs waiting for an intake, the one that's like a mutant improved motorcraft that Holly makes for them. Maybe I ought to spring for the Eddie after all?
Tgrease, thanks for the perspective. Yeah, kinda figured intakes would be the same between cars and trucks.

[Stuka]

JMO - if your standard is an aftermarket 600 CFM 'performance' carburetor, no way a factory 4350 is 25% larger (750CFM). Typically factory carburetors are intentionally undersized, for better fuel control under all conditions. Fuel economy has always been a thing, even in the days of cheap gas.

Spread bore carbs always have high CFM ratings due to the gigantic secondaries. The 4350 was originally intended for use on Ford big blocks (typically found on 460s). However, I was a bit off. Its 715 CFM after looking it up. I was thinking of the QJet 1901 that is 750.

Thanks, guys.
Stuka, your old Cherokee still had the oem cam, right? Your report based on a simple carb/intake swap is encouraging. I have one of those Summit Racing 600 cfm 4bbl carbs waiting for an intake, the one that's like a mutant improved motorcraft that Holly makes for them. Maybe I ought to spring for the Eddie after all?
Tgrease, thanks for the perspective. Yeah, kinda figured intakes would be the same between cars and trucks.

Yes, it had the stock cam.

From what I have heard the M2008 (assuming thats the one you have) is a pretty decent carb for the money.

[9.3x62]

Yes, I think that's the one, if i remember. I've been sitting on it for a while. Bigger fish to fry, lately, like tranny installs and what not.

[devildog80]

Just scored this over the weekend, and hoping it will do the job swapping out the OEM intake and MC2150 carb, to find more ponies inside the 401.
Old (74 yrs old) AMC mechanic has a shop out of his house now, with some beautiful AMC cars in his stable, so riding on faith he did me right on it. I have a new 1406 clone to get started, but preference would be a Qjet. Will take heed of comments for best carb, just like the smaller primaries.

20231202_100247 by Scott Weckerly, on Flickr

[Stuka]

Nice score!

That’s a square bore intake. So an Edelbrock or Holley/Clone will work. There are adapters to put a QJet onto one of these. But they are pretty tall to keep the bigger secondaries from hitting.

[devildog80]

Ok, so let the Qjet idea perhaps slip away with the wind......the others will work too, and can be tuned easily. Thought about a thin hood scoop, as it could provide heat relief under the hood, and bring in fresh air too, but might be an option if I go Qjet? Sure they do not raise that much, but just in case....

[tgreese]

Why don't you measure? You have the manifold height, and the adapter thickness will be given in the sales listing. Likely you will also need an insulating spacer. Low profile air cleaners exist. Quadrajet parts sellers online should be able to tell you how much height you need to clear the air horn.

[devildog80]

Will do that as just bringing it home I need to map out all the fittings needed, what is coming off the truck now, and overall fitment issues going back on, to be sure it is a one & done when ready. I am sure a Qjet will fit just fine, without thinking I need to cut the hood, but that was in mind anyway for heat relief living in the desert. And will be some time before I would be looking at a new carb, as cost is prohibitive right now being out of work. Looking local to find a functioning carb, and one closer to the year truck (84) it is going on. That I do like better than throwing $$$'s at a grocery getter/a few local camping trips vehicle. For my newer truck I need to use cross country for weddings/funerals and such, yes it gets the big bucks to be in prime condition. And I expect to be working on the GW some, which is why I have it.
Thanks for the feedback.....now back to original thread question.