best carb for off road?

[vancelot69]

Sorry if this has been posted before. When searching, I only saw one thread related, but he was asking which of the carbs he had was best. I would like to know which carb currently on the market (read: new) is best for off roading. I saw the 4-wheeler article from 2001 that said the Q-jet style is the best, but I have heard you can't get them new anymore. A co-worker suggested Holley Truck Avenger, and when I Google "off road carburetor" one of the links is to Summit Racing Edelbrock Thunder series AVS Off-Road carburetors. I have thought about fuel injection, but I don't have a grand to pop for that right now, plus the metal work to get the O2 sensors on the exhaust, so I'm trying to keep it on the cheap, even though a $500 carb isn't really cheap - may as well save up another $500 and get the injection kit at that point...

Anyway, any thoughts appreciated.

Thanks!

[cadillac_al]

Nothing has changed. The Qjet is better off road in technical rock crawling and easy starting. Cliff Ruggles can sell you a rebuilt carb that is better than new. Lars (I forget his last name) can also sell very nice Qjets. Square bore carbs with the bigger primaries are peppier off idle and not so docile over the rough terrain.

[webfoot]

The pool of good cores isn't going to last forever, that is for sure. The tricky part can be finding a good one.

They aren't voodoo magic to tune or rebuild either!

[Zoomad75]

Q-jet. The truck avenger isn't close, but it's better than the Edelbrock equipped with the off road stuff.

They are out there. It's that or go to a TBI style injection system. I wheeled a lot with my worn out 350/q-jet and it never failed me. Didn't matter the altitude or position pointed up or down, side hill or not. It always ran, never stumbled. Only things I would do to compensate for the extreme altitude where I was (8,000-13,000 ft) was bump the timing a little and give the carb a little faster idle. I wouldn't mess with the mixture. So it ran a little fat at altitude due to the lack of air, but it also meant it was one less thing to change back when I got home to the lower altitude.

I've seen the light and gone EFI with my LS swap though. Which makes the thought of going back to carb on anything off road much much less probable.

[rennat_2006]

Like everyone else mentioned q-jet ive been told is about the best. Holley truck avengers ive been told work alright. Regular holleys dont work worth a crap offroad from past experience. Ran a edelbrock 600cfm with a offroad spring kit i believe it was called in it and it wasnt too bad. It would leak fuel out of the passenger side throttle shaft if parked or sat on a hill too long.

[vancelot69]

Thanks for the replies, it is very helpful!

I searched for Cliff Ruggles on the forum and checked out this link http://67-72chevytrucks.com/vboard/s...d.php?t=538328. Then I Googled him and found this page that looks like his https://cliffshighperformance.com/ but without perusing the entire site, it looks like he rebuilds carbs you (I) send, and I don't have one to send in for rebuilding. So, in the forum link, on reply #7 Beetle linked to a Summit remanufactured q-jet. The part number on that page no longer exists, but it had a link to another page https://www.summitracing.com/tx/part...0216/overview/ that seems to be the same thing. Do you think I would have to do very much tuning to get that to work in an off road application? Or do you think it would be good to go straight out of the box?

Thanks again for the help!

[travisch]

Save the coin and keep saving until you can spring for the fuel injection. A well tuned carb is tough to beat but EFI is like having a little tiny guy sitting on the intake making adjustments for optimum performance every second.
The overall drivability of EFI is going to be much better than a carb.

On the flip side......EFI introduces electronics and $hit that can break but not be seen. A carb is 100% mechanical so a breakdown deep in the woods is usually much easier to diagnose and fix.

[webfoot]

Originally Posted by vancelot69

Thanks for the replies, it is very helpful!

I searched for Cliff Ruggles on the forum and checked out this link http://67-72chevytrucks.com/vboard/s...d.php?t=538328. Then I Googled him and found this page that looks like his https://cliffshighperformance.com/ but without perusing the entire site, it looks like he rebuilds carbs you (I) send, and I don't have one to send in for rebuilding. So, in the forum link, on reply #7 Beetle linked to a Summit remanufactured q-jet. The part number on that page no longer exists, but it had a link to another page https://www.summitracing.com/tx/part...0216/overview/ that seems to be the same thing. Do you think I would have to do very much tuning to get that to work in an off road application? Or do you think it would be good to go straight out of the box?

Thanks again for the help!

Any reman is still going to need suited to your engine, and it doesn't sound like they re-bush the throttle shaft on those so they still aren't ideal. They do look pretty though!

I'd look around for a good core, and then you can get Cliff's super rebuild kit. You give him your engine specs and he picks your rods, jets and idle air tubes.

If you don't feel comfortable doing that to a Qjet the summit one would probably work OK.

[jamyers]

Check out Mark at www.quadrajetpower.com

He's very reasonable on cost, fast, and a straight-up honest guy. I've got two of his Qjets, both work great.

[JustToxic]

I'm running a modified Demon Carb, I have had two Qjets catch fire on me while wheeling. Been running this demon for the last 6 years with ZERO problems.

[Stocker]

Originally Posted by JustToxic

I'm running a modified Demon Carb, I have had two Qjets catch fire on me while wheeling. Been running this demon for the last 6 years with ZERO problems.

Interesting, any idea what actually caused the fires? I've been running the oem q-jet (rebuilt a couple times) close to 42 years with no problems.

[JustToxic]

Originally Posted by Stocker

Interesting, any idea what actually caused the fires? I've been running the oem q-jet (rebuilt a couple times) close to 42 years with no problems.

The guy that built the demon carb said both carbs had float issues, that him and another guy could never get worked out.

[vancelot69]

I wasn't sure if I should necro this thread, or start a new thread, so I thought I'd just continue on my thread.

I decided to get the rebuilt quadrajet from Summit I linked to above (SUM-250216).

It came with the open gasket, which is .25" (1/4") thick.

The Holley I took off, which I think is a 4360, had the 4-hole gasket, which is 1/8" (.125") thick, and it had a manual choke.

My question is, should I use the open gasket, or get a 4-hole gasket, and should I get one that is 1/4" thick or 1/8" thick?

Thanks!

[jeffahart]

I use the 1/4 four hole, but you can use the one it came with. Thicker gives a bit more isolation for heat. Do torque to specs, I think it's 150 inch lbs. Don't over tighten.


j

[vancelot69]

Thanks jeffahart!

So, the reason for my query is because since I took off the 4-hole gasket, I was afraid that the open gasket would allow cross contamination (for lack of a better term) of the air/fuel mixture, so I thought I needed the 4-hole gasket to keep them all separated.

Then I got to looking at my pics again and noticed that the manifold has a trough between the two smaller holes and it looks like the open gasket that came with the carb has a notch cut out to account for the trough, and the carb has two big holes and a channel in the same area, which I assume are for the PCV fittings on the carb base, which would be closed off if I used the 4-hole gasket that doesn't have the notch cut out.

I feel like I'm over thinking this, but I have zero clues when it comes to carburetors. I did rebuild one over 20 years ago, but I didn't tune it after I installed it, but it seemed to run ok, so... haha

[jeffahart]

The gasket you have is correct. Yes over thinking. Install with that gasket.


j

[Ziegelsteinfaust]

Originally Posted by travisch

Save the coin and keep saving until you can spring for the fuel injection. A well tuned carb is tough to beat but EFI is like having a little tiny guy sitting on the intake making adjustments for optimum performance every second.
The overall drivability of EFI is going to be much better than a carb.

On the flip side......EFI introduces electronics and $hit that can break but not be seen. A carb is 100% mechanical so a breakdown deep in the woods is usually much easier to diagnose and fix.

Some of the aftermarket efi's have issues with dirt more so then a carb. Roadkills Vete cart had issue with Fi-techs getting sand in the shafts. This likely due to not needing to seal as effectively as a carb. This you can get a stuck throttle shaft from debris easier.

Lastly add a good filter sock for better protection of carb or EFI internals. Especially if you go I to the sand.

[special-K]

For a gasket I'd match to type of manifold. For any carb running off road a fuel regulator will make it better off road. Like it is about a necessity... and I don't run one. But I haven't been doing much where it matters in years.

Q-Jets causing fires? Had to be more to it. I can't believe a truck could run at all with a float stuck that bad. It couldn't have been running right. A fuel regulator could help that as well.

A friend and fellow member has been running his '69 Blazer off road in "obstacle" races for many year on a carb using a regulator, and he wins. He has made many changes to suspension and all over, but still runs a carb. This type of racing puts the vehicle through it all. Basically romping as hard as you can do on trails through the woods, hill climb (after going down just as steep and far), all out wide open, cutting new path over trees, and all

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