Four barrels rock!!

superj

superj

Active member
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This is the best of any of the carbs I have used on the jeep so far. Rock sold idle, accelerates like a sports car, 3500 rpm is 95 mph, no hanging idle or flat spot, it's just unbelievable how smooth and powerful the jeep is now. It's like my two barrel Holley but doubly better.

Here are some more pics for you guys

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Once I find a proper choke housing, I can pull that white tee out but for now, that's a huge vacuum leak without the tee.


For all you other 4.2 carb guys, forget the motorcraft 2100/2150 and just get a dang Holley 390 or 450 cfm four barrel and be happy
 
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dude, its so nice. the other guy with an 87 black wrangler, chris, has a 600 cfm edelbrock on his.
 
My Holley ran great on the street but not Offroad. That's why I went with the motorcraft, and it works great for what I use my jeep for, hunting and fishing where lesser vehicles cant go. Glad your jeeps back up to speed.
 

one of the old timers on jeepforum told me this was a very common set up back in the 70s. he said it worked very well off road, the offy and holley 450. which holley were you running?
 
It was a Holley 2150. Came off a 74 scout with a 304. It was pretty hard to find a rebuild kit, not even Holley had it. They told me about daytona carb. parts and they had it. Rebuilt the carb. And it ran great, just would not run on off camber situations. Every steep hill I had to climb to get to my fishing grounds it would keep flooding out, all the Offroad tricks like springs on the floats and extending the vent tubes, didn't work. Broke two axles because I had to floor it up a three foot ledge. Now I have the motorcraft, I can idle right up and over the same ledge. Its not as fast on the street but works great on the trail
 
Your making me jelous, My carb has issues and I have to adjust it every couple days for it to run right. Yesterday it was running awsome!! So smooth, felt like more power as well. Made me want a new carb really bad, then I come home and read your post. Maybe someones trying to tell me "go on, drop that coin and get a new carb" lol. Glad your happy with it..
 
It's making me think of just finding a wrangler with a blown motorto put the 302 into and keep this one this way.

So far, those tiny primaries are doing good job on the gas mileage. I am almost to 100 miles and not close to half yet. I knew I should have just put a four barrel on when I bought it but I kept being stingy and going with the cheaper two barrels. I finally spent the 40 bucks on eBay and am so much happier. If the gas mileage improves, like I expect it to, this will always be the first mod I tell any 4.2 guys to do
 
I think it will. There is also a 390cfm four barrel that I think might be better for a stock one but I think the 450 would be ok too.

I can't believe the other guy here in town is running a 600cfm on his 87 4.2. His mods are normal mods but his jeeps sounds like a monster and must run good because he has had the same set up for 6 years (I think is what he said)
 
Shoot, I wish I knew that before I got the motorcraft. I was looking at the Holley truck avenger when I was shopping for carbs. But all the info I was getting said it was to large, I believe it was a 450. Oh well, live and learn.
 

its a 470 and a few people are running that one on jeepforums. i thought about getting that one but this 450 showed up so i got it. i didn;t even know there was a 450cfm because the holley web site doesn;t list it. i was searching on ebay for ford four barrels and it popped up listed a 66 mustang four barrel, it didn;t say holley in the title so that must be why it went so cheap, no one was finding it on the searches.
 
Good for you man, take it easy on those tires. I can hear em screaming for help from here ha ha ha.
 

been saying this for years, finally someone gets it. I ran the same set up on a 86 CJ some 15 years back. I had a 390 CFM holley then eventually a jetted down 1406 edelbrock. eventually did a junk yard TBI on it, but the holley/offenhousen was the best running carb I ever had
 
JPS4jeep, I have a question for you.. not trying to jack the thread, but I have a holley 650 DP on a sbc, and I think the jets are somewhere around 72,s (maybe 65) primaries and 76 secondaries, If I jetted it down do you think it would help in mileage or performance. The guy that had the jeep before me raced it in the sand drags, I had to make a lot of changes to get it on the street and am wondering if he had it jetted for racing and it would run better jetted down. It runs rich and I have to adjust it every few days. Your thoughts???
 
69jeepcj said:
JPS4jeep, I have a question for you.. not trying to jack the thread, but I have a holley 650 DP on a sbc, and I think the jets are somewhere around 72,s (maybe 65) primaries and 76 secondaries, If I jetted it down do you think it would help in mileage or performance. The guy that had the jeep before me raced it in the sand drags, I had to make a lot of changes to get it on the street and am wondering if he had it jetted for racing and it would run better jetted down. It runs rich and I have to adjust it every few days. Your thoughts???
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Not trying to barge in but that jet spread is way to much. Should be no more than 3or four numbers apart. So if primarys are 65. Secondary's should be around 68. And 65 is about right for a sbc. You could try 62 65. If its got a nasty cam it will always run rich due to poor vacuum signal. Make sure your floats are set up below the sight hole that is a very common problem with hollleys and drivability is. Float level. As well as a blown power valve. Which will cause very rich mixture. Sorry I run 4 holleys and I have a lot of racing and street experience with them.
 

So the float level needs to be below the sight holes. I set mine how the instructions said and haven't touched them. You know how the rebuild kit days hold the bowl upside down and set clot parallel to housing? That's how mine is. I tied out some very mild off roadie with some climbing and angled spots and it never bogged or died
 
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