Topic: edelbrock carb problems

[DetroitTA]

i have a 79 with the 403, edelbrock intake manifold which doesnt sit any higher then the stock one...

ok so i thought id replace that rotting quadrajet on my car for an edelbrock 650 that i bought off ebay. i thought id be an easy swap, i was wrong.

after a bit of snags i managed to hook it up so the car will run, but it runs so rough...the car barely holds an idle when put into gear, the carb sits about 2mm higher (which is going to make shaker clearance problems) and i had to sacrafice the kickdown stud just so it will clear my intake manifold. plus im beginning to think im missing a peice off the carb.

i think it definatly needs some adjustments, however I dont know anything about carbs... i believe a trip to the mechanic is in order. has anybody ever run into these problems? has anyone put an aftermarket carb on a 403 with a working shaker? im just wondering if this is really a good idea considering my shaker just barley clears the hood, not to mention im afraid to run it with the shaker attached due to the fact that it will probably shake and slam into the hood.

if this is going to be too much of a hassle i think i may try just buying a rebuilt quadrajet or a rejetted one...

[ta78w72]

Have your Qjet rebuilt.  They're the best for your car.

I had a working shaker.  I took it apart and plugged up the opening (I have a spare uncut shaker on the shelf that I will install at some point).  The flap kept opening and closing and was a total nuisance.  You're better off leaving the car like it rolled off the assembly line.

But, I think everyone by now knows I like to keep these cars totally original.

On the edelbrock, you've probably got some vacuum problems or the carb was an ebay special.

On the carbs, I thought that the ones that came with the basic 400 and the  403 were 650, and the ones that came with the W72 were 800.  But I've read that they all were 800 so I'm not really sure anymore.

[silver-bullet]

hella... ditch the performer carb.  why? 1st off ,the stock Q-jet was a good performing carb in the 1st place. (if running and tuned right). 2.  sounds like you got issues with the carb.
the Q-jet has small primaries, for mad trottle response.  and massive secondaies to keep the party going.  
the 403 olds is a low end ground pounder.  so its like that carb was meant for that engine.
and ya, it is a big carb tho.  so tune  the secondaries to complement the primairies.  not just flooring it and having them come open, thats to much to soon. but rather, coming open cause the primaries are almost maxed.

i myself have 2 Q-jets.  a tuned down stock carb (but as clean as possible) for smog check in ca.  and a stage 2 Q-JET made by jet performance. i got from summit. damn what a differance!
my set up with the stock tuned down Q-jet bairly passes smog check.
with that stage 2 its a silver-bullet!
ohh...and its way better than the performer. and providing your not flooring it all day, the Q-jet is better on gas.
in short, a Q-jet tunned properly, and running right, is better on gas, and halls more a**!!!! (on a 403)

[DetroitTA]

i actually was lookin at the jet stage 2 q-jets on summit  and i just wanted someone to confirm it for me, looks like a pretty good buy, thanks for the advice.

[silver-bullet]

hey, anytime!  i forgot to mention that i do have alittle more cam than stock, with 1.6 roller rockers, and full length hedmans with 2 1/2 inch cutouts, into a pestkey cat. conv. (for smog) with a split pipe, into dynomax ultra flows.
ignition is msd hei w/ 6a box with a timing adjuster in the car. (for whenever the moment strikes) to go from 18* to 20 somthing +? all at the turn of a knob.

the stage 2 makes a hell of difference being tuned for more romp.
stage 3 might be to much unless you have a hardcore highly modified 403.
stage 1 is almost stock.  which is what id recomend, unless you got some mods.
the stock 403 dosent really respond to carb and head mods much. i mean, it does... but not like when i upgraded the cam to somthing alittle bigger. (its like a beast bangin on the hood sceaming to let him out).

within the reasons of the local smog laws. i choose a cam wisely!  and with true duel exhaust, thats like letting the beast out! and thats where my cutouts come in.
 and to much intake will kill the engine. literally!  its not a high rpm engine!  but its a low rpm ground pounder thats for sure!  the edelbrock rpm is to tall anyways, if you want your shaker to still be conected to the engine. (which is what im about).
so the only other choice out there for the CA streets is a eddy perfromer.
but.....ive heard that there is a old eddy torquer intake that is no longer made that will work with the shaker. ive never seen one with my own eyes tho.
anywho....this is what ive done to get my 10th annv. to go alittle fster, and stay drivable for long drives.  thu personal experiences and money.... :lol: ive whatched my stock 403 get more and more. some things worked, and some were a waist of hard earned dollars.  but ive watched it burn some rubber, and then burn some more rubber, and then burn a few transmissions. lol... im still workin on that part... but there is great thed on the site about a th400 upgrade. and thats what sharing info on this site is all about.
keep sharing info!!!!!!!!!!!!!!

yes... ido like my stage 2 tho.

[kitemare]

I'm also having carberator issues. I just had my Pontiac 400 rebuilt, put on a new 2 1/2" dual exhaust, & added an edelbrock higher flowing intake manifold. Now I'm haveing trouble with the carberator cutting out under hard acceleration at the low end until the RPM's get above 2,000 & then it takes off like a bat out of hell. It is also having trouble idleing at a stop light. The cam that was installed in the re-build was not an aggressive cam. My mechanic says that I need to have the carberator rebuilt. I'm not a mechanic so don't quite understand why a carberator that was working fine on an old tired motor is now having trouble with a newly rebuilt motor? I asked my mechanic why not get a new Holly 650 or something but he likes the idea of re-building the one that came on the motor.

I guess my question to the tech guys might have been answered on a previous post that it is better to re-build than buy a new aftermarket one. Also does anyone have a confirmation as to what size the carberator was that came stock on the non W72 car & do you need a carberator bigger than 650 CFM if you opened up the air intake & exhaust of your motor.

KM

[Eagle 1]

I think they were all 800 cfm carbs on the 78's.
You definately want a bigger carb than a 650 on any pontiac 400 engine.
Do as ta78w72 suggest and rebuild your original carb.
If you dont have one, they sale on ebay all the time.

[daruff]

I made the same mistake. I took off the old Q-Jet and put on a Edelbrock 1406.  It seems like i have really lost a lot of tourqe and HP. That was the worst decition i have made with my 78 T/A

[ta78w72]

Sometime around 1980 I replaced my QJet, which never worked correctly since I picked it up from the dealer, with a Holley.  I put the QJet in the Holley box and stored it in my garage.  In the late 90's, the Holley gave up the ghost and I was going to have it rebuilt.  Remembering all the problems I had with the Qjet, and how the dealer could never get it working correctly, I found a great carb rebuilder.  He took one look at the Holley and said the car would run a heck of a lot better with a QJet.  I went back home and got the Qjet which he rebuilt and installed.  The car did run better.  But the morale of the story is you have to find someone that knows what they're doing because there are some little tricks to getting them right.

Come to think of it, the Holley is now on a shelf in the garage!

[kitemare]

Thanks for the advise, I had my quadrajet rebuilt by someone that apparantly knows how to do it because my TA runs so good right now. It idles great in traffic & when I'm out on the freeway going 70 & floor it it flat out just flies.  

KM