Ok so i'm finally to the point of replacing the carb on my 77. I'm in debate over what carb to get. Summit has its own thats rather odd looking but decent. Anyone heard any good or bad from this carb? Looks like it would lack alot of adjustment options. If not I'm getting the Holley street avenger 670 and calling it good.

 

You'll get a zillion opinions on this one before the thread finally burns out, and for the most part it really depends on what you want to do with your car. The C3 purists out there all love Quadrajets-I have one on mine and it works well but they certainly have some very irritating idiosyncrasies. Quadrajets are difficult to rebuild, and good kits are getting expensive and harder to find nowadays, so unless you're a master at rebuilding them it's a job best left up to one of the acknowledged experts commonly referred on this forum. I would avoid an 'out-of-the-box' rebuilt QJet- for the most part they're junk. The Summit carb you're talking about looks to me like a copy or reissue of Ford's old Motorcraft 4300 from around 1970, configured pretty much like a Holley without the easily removeable float bowls. If you have a QJet on your car already and want to go with a square-bore carb like the Holley Avenger you're gonna want to look at squarebore intake(s) to fit it...adapter plates are cheesy at best. The 670 will work well with your 350 and of course Holleys are very tunable, which can be either a blessing or a curse depending on how proficient you are at setting them up properly. Also, beware of the intake's base height- there may be hood clearance issues to contend with and there will also be fuel plumbing issues to deal with if you switch. Enjoy!

 

Birdsmith post explains the reasons why I kept my replacement with a Quadrajet. My 73 is a stock engine, and I did not want to mess with too many changes with the spreadbore vs. squarebore , carb linkages, height to hood issues, etc.

I made it easy on myself and kept it stock.

Now if I was planning on upping the HP, and go with an aftermarket intake, then I might consider making all the other changes to go with a different make carb.

kdf

 

The Q-jet is a good carb all around IF it's built and set up correctly. The Q-jet is likely what came on your car so the connections should be pretty easy too. There are many sources that can help you do that, including Cliff Ruggles and Doug Rowe who each have very good books out on the subject, and Lars who used to post here had some very good papers on the subject. Maybe someone has a link to those papers and will post them here. If you do your homework, you can probably do the rebuild and set up yourself. You can also get high quailty parts from Cliff too. His standard rebuild kit is $35.00 and a HP kit for $80.

As for the performance aspects of the Q-jet, I have one on my big block (that's not stock, bigger cam, intake, valves, comp ratio, etc..) and it runs great, including good economy, so I'm obviously in the Q-jet camp. That being said, there's nothing really wrong with a Holley, they're easy to tune and rebuild, but don't seem to be as versatile to me. If I were going to run one, it'd be a spread bore type (like the Q-jet). Just make sense to me on the street to run off smaller primaries when cruising and the larger secondaries at heavy throttle.

 

Stick with the quadrajet. You can get decent rebuilt one from Jet or SMI, or have yours rebuilt by Cliff or Lars. Avoid the $299 rebuilts from your local auto parts store or the Vette supply catalogs. The Jet or SMI units use an electric choke, but are otherwise the same.

 

Yes mine has the stock Qjet on it, its just a turd and never been much of a fan of them. I've heard people say u can get them to run really well but I've delt with Holleys for years and got pretty good with them. I'm not against running a Qjet but they are out of my relm of expertiese so would hate to sink a lot of money into something I may or may not be able to fix and still end up getting a holley. The Qjet on the car now falls on its face if I try to open it to w.o.t. so that sucks all the fun of driving a V8 rear wheel drive car. Just need something with crisp throttle response, easy to adjust, and can put a few more ponies under the hood. If someone could id be happy for them to make me a believer in a Qjet, but as for now after all the cars and the dirt racing I've done I'm a solid believer in holleys.

 

Although I'm not a purist, I love the Quadrajet performance - both drag race and mileage - on my modified 406 SBC (check my profile).

 

Why not invest a few bucks in either Doug or Cliffs book and see what you think? I don't have Doug's book, but I do have Cliffs, and I can tell you it's well thought out, has great clear pics and if after reading through it (you should be able to do that in short order) you still want to go Holley, go for it. I have a good idea what's going on with your carb from your description and it's not a difficult fix. If your engine is stock or close to it, you can do the rebuild in an afternoon....

 

Ok ok I'll bite, so how do I get in touch with Doug or Cliff?

 

http://www.cliffshighperformance.com/index.html

i just recalibrated mine with Cliffs recommendations and help. It was easy and made a big difference. He may tell you that you need to reduce the size of your primary air bleeds. His book is a little unclear on this but its in there. Have your carb part number handy when you call him.

 

Hands down one of the best builders of the Qjet... he rebuilt mine for my ZZ4 in my 77

http://www.olescarb.com/id16.html

 

Now that you've gotten the expected responses from all the QJet fans out there, may I suggest that (providing that you've decided to attempt this rebuild yourself) you check two things immediately-
(1) After removing the top (airhorn) check to make sure that it's not warped by placing a straightedge across its underside. This is a very common problem with these carbs because people just can't resist the temptation to German-torque those two big bolts that hold the front of the carburetor down. Any warpage greater than about .010" is gonna give you fits and cause all kinds of leakage in the internal passages, making car run poopy.
(2) Check the throttle shafts for any play or looseness- just like a Holley, it won't want to idle properly if they're excessively worn. Neither of these issues can be fixed by throwing a rebuild kit at it...
.

 

Good points, however, both those can be fixed, and both are part of the inspection you'd do if you were to rebuild a Q-jet. So, I'd wait until you actually decide if you want to stay with the Q-jet or not before you rip it apart...

 

I am just got the 670 Street avenger and will be installing it in a week or so with summits version of a edelbrock intake. I should be posting results on here. I was a bit shakey on trying one of summit's carbs too so I went with the Holley name.