I need to change out the Rochester carb on my 1978 L-48.

I was going to go with just a rebuilt carb identical to the one I had.

I was suggested to look at some Edelbrock carbs.
I don't know much about them besides what they do and how they work.

What should I be looking for, and yes, I would like to get a little more power out of my weak L-48.

Edelbrock Performer Series Carbs

Any suggestions?

thanks in advance!!!!

 

Your stock manifold will not allow the use of the square bore edelbrock carb. you will have to buy something like the edlelbrock performer intake to use the edelbrock carbs.

 

thanks for the update!!!!

helps a lot!


i think i am gonna go with the edelbrock carb.

 

Theres nothing wrong with Q-jet it flows 750 CFM more then you will ever use on a L/48. I don't know if your car is stock but if it is the exhaust system on a 78 is pitifull you need to get rid of it first, then a recurve of your dist. will help. If your set on a new carb want the edelbrock the 650 CFM, elecric choke # EDL-1806 is calibrated for moderate high performance street. If I were doing it would have a holley but thats me.


Besides exhaust if you really want to wake your car up keep the Q-jet and
take the $350.00 for the new carb plus the $120.00 for another manifold
put that money into getting rid of your 76cc chamber very poor airflow factory
heads.

You don't have any airflow problems with the carb you have now, you do have
very poor compression and poor airflow with the heads.

 

Little Mouse is pretty close to the truth about where you should be focusing if you want to make your L-48 breath better.

You aren't specific about the symptoms you're having with your Q-Jet, but even so, I wouldn't throw the baby out with the bathwater. When I first got my 'Vette, I, too had some flooding and other issues with mine, but with the installation of an overhaul kit and some jetting changes, it runs strong and isn't bad in the mileage dept. either.

So, if it were me I'd give the Q-Jet a second chance. It might not be your problem, anyway. Then, go for dual exhausts, timing work, then heads, and you'll begin to wake it up.

 

thanks for the extra info,

with in the next few weeks, I should have new Stainless Hooker headers and side pipes in hand and ready to throw on.

as for the edlebrock 1806, I was actually looking at the 1406.
I think the only difference is the "Qwick Tune" air valve for control over the secondaries.

 

So, you want to pitch a carburetor that was designed in the early '60's for one designed in 1950.

That makes a lot of sense.

BigBlockk

Later.....

 

No I have an edelbrock catalog, the electric choke 1406 is 600 CFM
- calibrated for fuel economy- thats a nice way of saying it is really lean calibrated on fuel, your improving your exhaust system last thing you want is a lean calibrated carb unless you care nothing about performance, you can't have it both ways either a carb is jetted real lean to stretch on fuel or its a little richer for better performance.

The 1806 is 650 CFM, electric choke, calibrated for- moderate high performance street, nice way of saying the carb has air/fuel ratio for a performance carb.

 

i haven't made any decisions, I'm still trying to learn about them.
Im not a gear head nor' mechanic.

 

ahhh, okay, looks like I'm leaning towards staying with a rebuilt Rochester.
and see how it performs with my new exhaust.

I appreciate all the info guys!
(minus the one sarcastic remark )

 

You didn't really say why you needed to replace the Carb. If it's a drivability problem, I can understand your situation. The #1806 is a very nice carb, it solved a drivability problem on another vehicle that had a Q-Jet on it. Fortunately for me I already had a manifold that accepted the 1806. There are adapter plates available for squarebore to spreadbore. I don’t know the adapter thickness and if it would create a hood clearance issue.
The last time I tried, I was able to buy a brand new Q- Jet from a website called the Carburetor Shop. I don’t know if I would get a rebuilt unless it was from a recommended shop. Depending on what the problem is, you may want to have your carb rebuilt.

 

The QJet is a great carb...does yours have a problem?

$600. and you can get a set of summit heads with 2.02 SS valves and seats shipped to your door...they are made by Dart and are identical to Darts Iron Eagle series...perfect for todays gas....they are 67cc's I think (maybe 64...dont remember)

Get a complete gasket kit for your engine...not just a top end kit....the headers will come with gaskets, header bolts and an alternator bracket (if needed)....use the gasket kit to repair any other oil leaks you may (or may not) have...also; do yourself a favor and put a new water pump and t-stat if you havent already.
Have new spark plugs and tune-up stuff....then adjust carb when done.

Your wanting to spend 12 tp 15 hundred on headers and sidepipes, then another 4 to 5 hundred on intake and carb.


Your L48 intake and carb would respond better to the heads and headers better than ...
...your L48 heads would respond to headers and the Edlbrock stuff.

Its all about maximizing flow.....right now your weakest link (considering the upgrades you want) are the heads...not the intake and carb.

You want to burn tires?....lose the emission crap, change the heads, add headers, and tune-up.....then later sae your money and get an intake, a carb,..... and electric fans to get free HP.




IMHO
Jim


PS.
They are emission/EGR delete plates ......if your state allows it.

 

After thinking about your situation, if your Carb is working OK and you just want some more power, for right now you can work with what you have. The Q-Jet is basically a good carb and if it's original, numbers matching and you would like to keep it that way, try tuning what you have. To find out if it's the correct carb, check the numbers on the rear of the body. Reference books will tell you the correct carb number for your year. Corvette by the Numbers and Rochester Carburetors are a couple that I use.
I am assuming the fuel/air screws are tached out, timing set, good manifold vacuum, good spark, throttle shafts are not worn to excess, etc.. You could try changing out the Secondary jets and adjusting when the secondary kicks in. If you or a friend that is good with Carbs removes the existing jets, they have a number stamped on them. You will also see how aggressive the tip is, the shape of the tip determines the flow. The right set of jets can make a big difference in performance. A got some jets from old Carbs, friends and Summit. Adjusting when the secondary kicks in can also make a big difference, too soon = Quadrabog, too late = lame perforamce. Q-Jets needs time and patience to get them right.

 

thanks for the info again guys!

I decided to find a "new" QJet identical to the one I have.

I appreciate everyone's help!
I'm still trying to find a place that has them in stock,
I can find them every where, but all out of stock.

Any one have any good places to check?

again its the QJet for a L-48 Automatic with Air.

 

how much does a new Q-jet cost, I was thinking rebuilt is all thats out there, holley has a couple carbs that are spread bore relacement for the Q-jet.
How much are rebuild kits for the Q-jet, are tuning parts still available for them ??

 

well when I said "new" i meant rebuilt.
I don't think you could find any new ones.

and I'm not sure how much rebuild kits are, I have not looked into those yet. and yes, you can find tuning parts, although rare, they are out there.

 

PM forum member Lars for any/all info pertaining to the Qjet. He'll rebuild or lead you in the right direction!

 

Lars apparently isn't doing carbs at this time. Rebuild kits are inexpensive and you could do it yourself. Go to NAPA and give them your carb part number and car info. Get a new, good quality float for the rebuild. Follow the directions and make all of the adjustments required. Your carb will then not be the 'limiting factor' on engine power.