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Old 03-22-2010, 10:44 AM   #1
bad68bowtie
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Question Anyone have an opinion on Jet Performance carbs?

I've been looking into getting a JET Performance Quadrajet for my '68. I'm running a 290 hp GM Performance 350 crate motor in the truck and I was looking at the 35002, the 750 cfm Stage 2 model. I feel like I've read a few decent things about JET products, but I figured I'd see if anyone had some direct experience and input regarding them. The whole reason I'm looking into getting this carb is I've been running and Edelbrock 1406 ever since I got my truck (5 years ago) and have never been very satisfied with it, and that's with having it rebuilt a year and a half ago.

I have someone I trust who can get the Quadrajet tuned and dialed in for me, so I'm not worried about fighting that battle, but I just wanted to see if anyone had some reviews of JET stuff. I've heard enough horror stories of people dealing with Demon carbs to turn me off from those and I figured I'd try out the Quadrajet before going with a Holley. Thanks, y'all.
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Old 03-22-2010, 07:27 PM   #2
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Re: Anyone have an opinion on Jet Performance carbs?

Does the guy you're gonna have dial it in do rebuilds?
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Old 03-22-2010, 08:31 PM   #3
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Re: Anyone have an opinion on Jet Performance carbs?

Just like any other performance carb (holley, edelbrock, BG, etc...), it will use a somewhat generic combination of air/fuel passage sizes so that it will work "pretty good" on a wide variety of performance engines. It's really nothing all that special, but should work OK, and look like new.

I would imagine the stages are like a 1, 2, and 3? -- all 3 just use a little different combination of passages and jets to get you in the ballpark.

I bolted the qjet on my junkyard 350 that I had self-tuned to my 400+ HP 350, and it seems to work pretty well without any changes.

I think the main thing with a qjet is they are generally emissions carbs, and are tuned specifically for the engine they came through on. Throw that onto something with even just headers and a cam swap, and will probably be missing out on a lot of the potential.
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Old 03-22-2010, 08:58 PM   #4
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Re: Anyone have an opinion on Jet Performance carbs?

If you switch from a squarebore like the Edelbrock/AFB to a Q-jet... you'll need a spreadbore manifold. Unless you're running an adapter on a stock spreadbore manifold now.

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Old 03-22-2010, 10:16 PM   #5
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Re: Anyone have an opinion on Jet Performance carbs?

Cant comment on "Jet" but will say without reservation I am VERY happy with my SMI Quad I would highly recommend Sean Murphy Inductions plus he a little guy that can use our support. Give him a call 714-843-9169, smicarburetor.com. There is much to consider when setting up a Q-jet and Sean knows how! I bought a "rebuilt" ebay carb from a board member for my DD 68 350-400 pick-up when I received it I immediately knew it was not rebuilt replated and pretty yes but definitely not rebuilt, so I called SMI talked to them sent it to them about two weeks later my carb showed up took it out of the box installed it the ONLY adjustment I had to do was the idle speed its been on for about nine months or more and NO problems! Do what you want but the carb for the 500 Cad will be from SMI. Oh and I will also say my fuel mileage is as good as I could ever hope for, dont really keep track cus it costs what it costs but its the best its ever been!I have including the purchase price and the SMI rebuild/recalibration around $300+ invested and am more than satisfied!
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Old 03-23-2010, 01:02 AM   #6
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Re: Anyone have an opinion on Jet Performance carbs?

Quote:
Originally Posted by Jim_PA View Post
Just like any other performance carb (holley, edelbrock, BG, etc...), it will use a somewhat generic combination of air/fuel passage sizes so that it will work "pretty good" on a wide variety of performance engines. It's really nothing all that special, but should work OK, and look like new.

I would imagine the stages are like a 1, 2, and 3? -- all 3 just use a little different combination of passages and jets to get you in the ballpark.

I bolted the qjet on my junkyard 350 that I had self-tuned to my 400+ HP 350, and it seems to work pretty well without any changes.

I think the main thing with a qjet is they are generally emissions carbs, and are tuned specifically for the engine they came through on. Throw that onto something with even just headers and a cam swap, and will probably be missing out on a lot of the potential.
"generic combination of air fuel mixture"? A carburetor is a fine apparatus in it's own way and there is nothing "generic" about any carb, and it is not the same as a "new" Qjet- Anyways... to the question at hand.

YES the Jet Performance Qjet carbs are good, I am considering one for my truck, stage 2 as well........ HOWEVER, if you want a great Qjet carb.... buy a SEAN MURPHY Qjet, which is what I will eventually get. You can order by stages or you can have it custom built to meet your exact application.
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Old 03-23-2010, 06:16 AM   #7
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Re: Anyone have an opinion on Jet Performance carbs?

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Originally Posted by JFP Motorsports Div View Post
"generic combination of air fuel mixture"? A carburetor is a fine apparatus in it's own way and there is nothing "generic" about any carb, and it is not the same as a "new" Qjet- Anyways... to the question at hand.

YES the Jet Performance Qjet carbs are good, I am considering one for my truck, stage 2 as well........ HOWEVER, if you want a great Qjet carb.... buy a SEAN MURPHY Qjet, which is what I will eventually get. You can order by stages or you can have it custom built to meet your exact application.
Sean Murphy also sells generic carbs. Not only that, but you'll get whatever POS core he has available.

And yes, everything about an entry-level performance carb is generic. How many people play with air bleeds and idle restrictions?

Maybe you should re-read what I said, because you clearly don't get it.

Last edited by Jim_PA; 03-23-2010 at 06:26 AM.
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Old 03-23-2010, 05:57 PM   #8
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Re: Anyone have an opinion on Jet Performance carbs?

Cool, thanks for the input guys.

I guess it would be beneficial if I put a link to exactly what I was looking at- http://www.summitracing.com/parts/JET-35002/

I'll look into the SMI carb, it actually is a little cheaper, but we'll see what happens. I hate to say this, because I do like to support the lesser known guys and whatnot, but it's real convenient for me to buy things from Summit because I don't have to deal with shipping. It just eases my mind if I have a problem with a product knowing I don't have to box anything up and ship it back and all of that hassle.
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Old 03-23-2010, 06:34 PM   #9
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Re: Anyone have an opinion on Jet Performance carbs?

FWIW I put one of the Summit brand Q-Jets on my '76 Monte Carlo and it performed flawlessly. I was prepared to dial it in as I have a fair supply of Q-Jet tuning parts but it was perfect right out of the box for my application. I set the idle speed, tweaked the mixture screws a tiny bit and it was good to go. For what it takes to find a good core now and rebuild it they are well worth the money. I'll be putting one on my '66 when I get the 355 done.
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Old 03-23-2010, 07:21 PM   #10
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Re: Anyone have an opinion on Jet Performance carbs?

The best ones (IMO) are the 78-85 truck carbs. Carbs with a single electronic plug are OK as you can just disconnect the dual volume accelerator pump. You can also cut off and epoxy the solenoid, but it's only a visual thing.

If it has a TPS AND a plug on the top, it's bad.
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Old 03-23-2010, 10:02 PM   #11
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Re: Anyone have an opinion on Jet Performance carbs?

Quote:
Originally Posted by bad68bowtie View Post
I've been looking into getting a JET Performance Quadrajet for my '68. I'm running a 290 hp GM Performance 350 crate motor in the truck and I was looking at the 35002, the 750 cfm Stage 2 model. I feel like I've read a few decent things about JET products, but I figured I'd see if anyone had some direct experience and input regarding them. The whole reason I'm looking into getting this carb is I've been running and Edelbrock 1406 ever since I got my truck (5 years ago) and have never been very satisfied with it, and that's with having it rebuilt a year and a half ago.

I have someone I trust who can get the Quadrajet tuned and dialed in for me, so I'm not worried about fighting that battle, but I just wanted to see if anyone had some reviews of JET stuff. I've heard enough horror stories of people dealing with Demon carbs to turn me off from those and I figured I'd try out the Quadrajet before going with a Holley. Thanks, y'all.
I bought this exact carb for my 355 and love it. It didn't need much tweaking right out of the box and the performance was amazing. The Qjet I had before was leaking out of the throttle shafts and was in need of a major rebuild so I sprung for the JET product. I got the electric choke model and have no regrets.
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Old 03-24-2010, 12:45 AM   #12
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Question Re: Anyone have an opinion on Jet Performance carbs?

Quote:
Originally Posted by Jim_PA View Post
The best ones (IMO) are the 78-85 truck carbs. Carbs with a single electronic plug are OK as you can just disconnect the dual volume accelerator pump. You can also cut off and epoxy the solenoid, but it's only a visual thing.

If it has a TPS AND a plug on the top, it's bad.
Jim, I think I have an 83 truck carb with the electronic plug. I bought it online not knowing it was different than the old ones.

What is the TPS you talk about? I just know it's got some sort of electrical connection on top. Got any pics of what you're referring too? I'd like to run it eventually if I can...
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Old 03-24-2010, 07:34 AM   #13
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Re: Anyone have an opinion on Jet Performance carbs?

Carbs with one electric plug on the top of the air horn are for the purpose of controlling a temperature controlled accelerator pump shot (there is NO computer involved with this). When engine is cold, it gives a full pump shot. When coolant temp is high, the solenoid pops out, and blocks off a portion of the accelerator pump volume.

Best example I can find is in an ebay auction...
http://cgi.ebay.com/ebaymotors/ROCHE...Q5fAccessories


The other arrangement has 2 electronic plugs... one in the same spot on the top of the air horn (looks similar, but it's a completely different function...), and a second plug over on the throttle linkage side, down close to the idle mixture screws. These carbs are the CCC version, that use a TPS sensor, a computer, and an electronic metering rod system that raises and lowers the metering rods from signals from the TPS and the computer. I can only imagine these can be converted to use a conventional vacuum controlled power piston assembly, but I've never tried.

Here's a pic of one that requires a computer
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Old 03-24-2010, 10:13 AM   #14
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Re: Anyone have an opinion on Jet Performance carbs?

[QUOTE=Jim_PA;3876837] How many people play with air bleeds and idle restrictions?

QUOTE]


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Old 03-24-2010, 10:29 AM   #15
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Re: Anyone have an opinion on Jet Performance carbs?

[quote=prostreetC-10;3879159]
Quote:
Originally Posted by Jim_PA View Post
How many people play with air bleeds and idle restrictions?

QUOTE]


Why I do!!!!
Yeah, but you aren't the average joe blow who buys x carburetor from summit, bolts it on, plays with the jets, and walks away from it
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Old 03-24-2010, 08:16 PM   #16
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Re: Anyone have an opinion on Jet Performance carbs?

i agree, very few people could tell you where the bleeds are much less which one is the idle and which the high speed. there are several good carbs on the market, but most all have a generic tune unless you pay to have it custom tuned. even then it is not a one time thing, it is something you have to make several educated changes to get it perfect. the jet carb is a good carb, but it still has some idle circuit issues that you don't get corrected with any stage of there carb. these are not wonder carbs but there generic tune will work with many applications, it is much better than trying to put a stock carb off something on a different application. the qjet is not nearly as forgiving as a holley or edelbrock carb for the average person.
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Old 03-24-2010, 11:34 PM   #17
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Re: Anyone have an opinion on Jet Performance carbs?

I didn't read through ever post so this might have been covered but you have to be careful with these "super tuned" carbs. If you have any carb that has really been "worked" for a specific setup, it might work worse than those generic tuned carbs. It's funny to see all the Pro Systems, Biggs, JDR....etc carbs out there on ebay that people pay a ton for just because of the sticker on the top of the fuel bowl. They have no idea what the carb was setup to do. They pay a TON of money for it and wonder why it runs like crap on their motor. Most people can't tell the difference between a blow thru or supercharger carb from a standard one.

LOL.......I think I started rambling and got off track somehow. What was the question??? LMAO

Bottom line is that it's really hard to nail down a carb tune without some kind of an O2 sensor and data recorder. Even a dyno won't give you an accurate sim like being on the road.

Gunna go take some more Nyquil
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Old 03-27-2010, 07:50 AM   #18
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Re: Anyone have an opinion on Jet Performance carbs?

I haven't read the thread, so I don't know what's been posted above.

My experience with a Jet~
I called the tech people at Jet and told them what I wanted-- a bone stocker for a '72/350/automatic, with an electric choke. They recommended the part number and I bought it.

Bolted it on and the truck popped right off, but ran pig rich (blew black smoke out the tailpipe. Made a big, black soot stain on the garage wall) and had an off-idle stumble.

I tore it down for a look. When the description says "recalibrated" what they're doing is plugging the air bleeds, fattening up the jets, and a few other mods. It's no wonder it didn't run right. The pièce de résistance was the air horn. The blade that the accelerator pump pivots on had been broken off, JB welded back on, then alodined. It fell off the first time I pushed the pivot pin out to take it apart.

Wasn't toooo impressed with the Jet.
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Old 06-18-2011, 08:28 PM   #19
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Re: Anyone have an opinion on Jet Performance carbs?

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Originally Posted by Jim_PA View Post
Sean Murphy also sells generic carbs. Not only that, but you'll get whatever POS core he has available.

And yes, everything about an entry-level performance carb is generic. How many people play with air bleeds and idle restrictions?

Maybe you should re-read what I said, because you clearly don't get it.
Hi Jim. when did you visit my shop to see what I have available? you suggest that possibly a CCC Q-jet could be converted to use a vacuum operated power piston. The lack of the vacuum tower in the float bowl might be a serious hurdle to overcome...But who needs a system that constantly reacts to changes in MAP when you have fixed air bleeds, right?
Perhaps you might enlighten us all to purpose of the air bleed and how it effects carburetor function. being the air bleed master and all....
What was the name of your Company again?
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Old 06-18-2011, 08:36 PM   #20
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Re: Anyone have an opinion on Jet Performance carbs?

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Originally Posted by sean murphy View Post
Hi Jim. when did you visit my shop to see what I have available? you suggest that possibly a CCC Q-jet could be converted to use a vacuum operated power piston. The lack of the vacuum tower in the float bowl might be a serious hurdle to overcome...But who needs a system that constantly reacts to changes in MAP when you have fixed air bleeds, right?
Perhaps you might enlighten us all to purpose of the air bleed and how it effects carburetor function. being the air bleed master and all....
What was the name of your Company again?
Welcome to the forum Sean. I'm afraid your questions to Jim will go unanswered. Jim has not posted here since last august.
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Old 06-18-2011, 09:10 PM   #21
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Re: Anyone have an opinion on Jet Performance carbs?

Welcome to the forum Sean. I have heard great things about your carbs, and will be sending you my quad for my blazer!
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Old 06-19-2011, 03:51 PM   #22
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Re: Anyone have an opinion on Jet Performance carbs?

Buy a decent used 76-77 Q-Jet somewhere and Cliff Ruggle's book, and you'll be way ahead of the game.
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