replacing my carb and intake manifold on a 305/350/383 - Third Generation F-Body Message Boards

79_T/A_guy · 07-02-2009, 02:41 AM

Hi, this may be a hard question and im curious what you guys think.

Right now my car is a 1984 TA with a 305(info under my name) anyways here is the deal.

My carb is performing poorly. it floods and is unreliable, and i want to replace it with something that will stand out alittle.

now here is the hard part, i have a 305 in right now. i plan and seriously intend to remove the 305 with a 350, and im seriously considering putting that 350 under some serious work and make it a nice 383.

now i want to replace the intake manifold and carb now on the 305 and then when i get the 350/383 done i want to toss the intake manifold and carb onto that.

now im unsure how much CFM's i would need to get. i figure it would be around a 650CFM carb but im unsure.

lastly i ran across this on Jegs and was wondering if this would even work for my 305 and be able to be put onto my 350/383 when its done. here is the link to the carb and intake manifold unit: http://www.jegs.com/i/Edelbrock/350/5425K/10002/-1

i love the looks of dual carbs and if i could buy this bolt it on, and still use it later when i up the HP with a new motor id be in heaven, so anyways any ideas or other recomendations would be great. i was originally looking at a edelbrock performer intake and performer carb but cant find the performer series anymore. I DO WANT TO USE EDLEBROCK NO OTHER BRANDS UNLESS I HAVE TOO.

thanks
-alex

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Ozz1967 · 07-02-2009, 08:02 AM

Quote:

Originally Posted by 79_T/A_guy

Hi, this may be a hard question and im curious what you guys think.

Right now my car is a 1984 TA with a 305(info under my name) anyways here is the deal.

My carb is performing poorly. it floods and is unreliable, and i want to replace it with something that will stand out alittle.

now here is the hard part, i have a 305 in right now. i plan and seriously intend to remove the 305 with a 350, and im seriously considering putting that 350 under some serious work and make it a nice 383.

now i want to replace the intake manifold and carb now on the 305 and then when i get the 350/383 done i want to toss the intake manifold and carb onto that.

now im unsure how much CFM's i would need to get. i figure it would be around a 650CFM carb but im unsure.

lastly i ran across this on Jegs and was wondering if this would even work for my 305 and be able to be put onto my 350/383 when its done. here is the link to the carb and intake manifold unit: http://www.jegs.com/i/Edelbrock/350/5425K/10002/-1

i love the looks of dual carbs and if i could buy this bolt it on, and still use it later when i up the HP with a new motor id be in heaven, so anyways any ideas or other recomendations would be great. i was originally looking at a edelbrock performer intake and performer carb but cant find the performer series anymore. I DO WANT TO USE EDLEBROCK NO OTHER BRANDS UNLESS I HAVE TOO.

thanks
-alex

I also have an 84T/A...so my primary question Alex, is do you need/require emissions? The factory Q-jet that comes on it, if in proper running condition is more than enough to run your 383 because it will pull 750CFM. Edelbrock does make a spread-bore quadrajet style carb that will work and is a replacement for the Fatory Qjet that's on the car now. They're a little touchy to tune but they'll keep up with just about anything for power.

Also, since your car most likely has all of the emissions stuff on it (unless you removed it or it was already removed) you will need to get a carb that's electronically controlled so it will pass the tests. Lastly, looking at that set up in your link, while it will work for a 305/350/383 though I don't believe it will fit under your hood unless you get a cowl-induction hood or a drop base air-filter. Even running something as simple as a Performer AirGap or Performer RPM intake is too tall with the factory set up to fit under our hoods. I'm running an Edelbrock Performer on mine, it's better than stock but still fits under the hood. Hope this helps!

79_T/A_guy · 07-02-2009, 02:33 PM

thanks for the info but i plan on removing the emissions stuff, i dont care at all for the emissions, ac, heat, i just want the car to run, drive, and not leave me stranded. now my car is specifically a 15th anniversary firebird so its kinda got a cowl hood but i think its offset so far that it wont help me with the carb set up in the link.

also i was wondering the dual carb is a manual choke?

as far as the cowl induction hood goes i was looking to get one, so if i have to get one ill probably just get it that much quicker.

lastly if it matters i would like this car to become my daily driver.

LB9Iroc87 · 07-02-2009, 02:49 PM

with you saying that this is going to be your daily driver i would like to say that my dad has a 55 chevy with a 383 in it toped of with a RPM air gap intake and a 650 demon and it runs incredibly great, he can he pull 16mpg on the highway running 70mph. I really dont think there would be any since in getting a dual carb setup because its twice the hassle on tunning and why do it when you only really need one carb.

79_T/A_guy · 07-02-2009, 02:58 PM

i was thinking mostly as i have always liked the look of dual carbs. however i think i might just save the dual carb'd engine idea for another project.

so would a 650CFM carb work for my needs, whether it be a 305, 350, or 383?

if thats the case i might just pick up the edelbrock performer intake and carb, which is about half anyways.

LB9Iroc87 · 07-02-2009, 03:49 PM

i think a 650 would do the job, we had to put smaller jets in the 650 on my dads 383 bcuz it would run rich so i believe a 650 could keep up just fine

five7kid · 07-02-2009, 05:10 PM

Quote:

Originally Posted by 79_T/A_guy

im curious what you guys think.

Remember, you asked. You probably aren't going to like what I have to say.

Quote:

Originally Posted by 79_T/A_guy

My carb is performing poorly. it floods and is unreliable

A simple rebuild would stop the flooding (if in fact it is flooding) and make it reliable. I have not once had a problem with my stock carb in 10 years of daily driving. It has also been raced during the summer, and the only issue we've had with that is needing to replace the choke pull-off a couple of years ago (didn't cause a problem for daily driving).

Quote:

Originally Posted by 79_T/A_guy

i want to replace it with something that will stand out alittle.

I'm not sure quite how to quantify that.

Quote:

Originally Posted by 79_T/A_guy

now here is the hard part, i have a 305 in right now. i plan and seriously intend to remove the 305 with a 350, and im seriously considering putting that 350 under some serious work and make it a nice 383.

now i want to replace the intake manifold and carb now on the 305 and then when i get the 350/383 done i want to toss the intake manifold and carb onto that.

You may be able to do that with the intake, but the carb will be a compromise on at least two of those engines.

Quote:

Originally Posted by 79_T/A_guy

now im unsure how much CFM's i would need to get. i figure it would be around a 650CFM carb but im unsure.

It would be different for a 305 vs. a 350 vs. a 383.

Quote:

Originally Posted by 79_T/A_guy

lastly i ran across this on Jegs and was wondering if this would even work for my 305 and be able to be put onto my 350/383 when its done. here is the link to the carb and intake manifold unit: http://www.jegs.com/i/Edelbrock/350/5425K/10002/-1

If by "work" you mean "run", the answer is "yes". If by "work" you mean "run well", the answer is "probably not". Of those three engine, it would be closest suited for the 383. But, keep reading.

Quote:

Originally Posted by 79_T/A_guy

i love the looks of dual carbs...

Okay, now we're getting somewhere. Looks is what's most important to you. That being the case, it's a good looking set-up.

Quote:

Originally Posted by 79_T/A_guy

... and if i could buy this bolt it on, and still use it later when i up the HP with a new motor id be in heaven, so anyways any ideas or other recomendations would be great. i was originally looking at a edelbrock performer intake and performer carb but cant find the performer series anymore.

The most critical piece of information is still to come.

Quote:

Originally Posted by 79_T/A_guy

I DO WANT TO USE EDLEBROCK NO OTHER BRANDS UNLESS I HAVE TOO.

Finally we get to the nitty gritty - You aren't as interested in performance as you are in using an Edelbrock carb. That being the case, we can work from there.

That dual carb set-up is simply too big for any of the engines you're talking about, unless you spin the 383 to 9000 RPMs. One of the carbs is big enough for the 305, and the 383 at 6000 RPMs is still only going to need 665 CFM. That intake manifold may be good to 5500 RPMs before it dies out, 5000 RPMs is probably more like it. On the street, the thing is going to run like a pig. Under wide open throttle, the secondaries are only going to be open about 1/4 of the way.

My recommendation would be to fix whatever is wrong with your stock q-jet and get a Performer RPM Spreadbore intake for it. It'll be fine on a stock 305, it'll do well on a mild 350, and it will completely support a very stout 383. And, it will drive well for any of them, be reasonable on gas on the street, and run like gangbusters for all of them.

The final nail in the coffin is it will cost less than a third of what that dual quad set-up would cost you.

Don't forget you'll need a new distributor for the dual quad set-up.

That is what I think.

79_T/A_guy · 07-02-2009, 09:41 PM

thank you for the info, but i have decieded against the dual carb. it would be cool but in the end i would rather performance over cool.

i have a feeling you dont care for edelbrock.

is there a reason?

and i have now decieded i would like to get the 305 running good, and when i get the 305 running very nicely ill then start to build the 350, and the more parts i can use the better.

so for a 305 would a 500cfm carb work best considering i would put a mild cam in the engine and have a mild rebuild on the 305.

lastly i would really perfer to use edelbrock and realize i will use a electric choke carb no matter the brand. would say a holley carb work noticeably better?

vladicore · 07-03-2009, 12:21 AM

edelbrock carbs are easy to tune n work on but arent known for there performance like the holley and demons ect....

im sure thats what he was gettin at in his reply

five7kid · 07-03-2009, 12:24 AM

Quote:

Originally Posted by 79_T/A_guy

i have a feeling you dont care for edelbrock.

is there a reason?

Compared to a q-jet:
Older design
Not as adjustable
Not as adaptable
Not as good on fuel
Not as capable for power

Make that a CC q-jet, and economy is even better with no sacrifice of the rest.

If you "need" to replace the q-jet, an Edelbrock is a downgrade in every way. If you don't need a Holley, keep the q-jet.

Quote:

Originally Posted by 79_T/A_guy

and i have now decieded i would like to get the 305 running good, and when i get the 305 running very nicely ill then start to build the 350, and the more parts i can use the better.

so for a 305 would a 500cfm carb work best considering i would put a mild cam in the engine and have a mild rebuild on the 305.

The q-jet is the right carb.

Quote:

Originally Posted by 79_T/A_guy

lastly i would really perfer to use edelbrock and realize i will use a electric choke carb no matter the brand. would say a holley carb work noticeably better?

Better than an Edelbrock, but not as good overall as the q-jet.

79_T/A_guy · 07-03-2009, 07:26 AM

hmmm, in this case how hard is rebuilding a q-jett?

i have rebuilt dual motorcycle carbs to the point where i could do it with my eyes closed. would this be around the same level?

any sites sell a q-jett rebuild kit that you would recommend?

Ozz1967 · 07-03-2009, 04:42 PM

Quote:

Originally Posted by 79_T/A_guy

hmmm, in this case how hard is rebuilding a q-jett?

i have rebuilt dual motorcycle carbs to the point where i could do it with my eyes closed. would this be around the same level?

any sites sell a q-jett rebuild kit that you would recommend?

Summit Racing and Jegs both have a book or two on rebuilding Qjets. Jet Performance Products also sells Qjets and the rebuild kits as well as the Jets, secondary metering Rods and Hangars for them. It's where I picked up my carb. All I ahd to do what asjust the idle and drop in a new set of secondary rods before taking it to a dyno to have it chassis tuned by a pro. LOL Never could get my rich/lean mixture right. hehe

ctsplicer · 07-03-2009, 09:41 PM

Over the years I have used almost every carb out there,holley,rochester,edelbrock,proform,demon,predator etc.I stumbled upon a carb I now have on my 64 cutlass with a 383 stroker in it.It is a quickfuels technology 680 CFM with vacuum secondarys,double pumper,and electric choke.Without a doubt it is hands down the best carb I have ever used and a lot of people I have shown it to who have also seen the difference in perfomance in my car have bought it for there cars and love it.You can buy it at any good speed shop or Summit racing.

79_T/A_guy · 07-24-2009, 01:07 AM

hey guys so i have chosen to rebuild the q-jet, however i am unsure about the exact kit i need. summit seems to have kits specifically for trucks and i cant find one i would use.

any help would be great.

Ozz1967 · 07-24-2009, 10:40 AM

Quote:

Originally Posted by 79_T/A_guy

hey guys so i have chosen to rebuild the q-jet, however i am unsure about the exact kit i need. summit seems to have kits specifically for trucks and i cant find one i would use.

any help would be great.

The carbs for the trucks are the same as for the cars, you just need to figure out your part number and get on the line with their tech department. The Qjets were used on alot of vehicles for alot of years.

Or...I would call jet performance products.Jet Performance and talk to them as they are one of the premier Qjet rebuilders/makers out there now. They are the ones who I bought my carb from (stage 1 Qjet) for my 84 T/A...all I had to do was change the secondary metering rods when up upgraded to my 350. Just tell them what you are trying to do and they will hook you up with whatever you need. Good luck!

naf · 07-26-2009, 02:29 PM

A rebuild kit is essentially a set of replacement soft parts for the carb. Any parts store will carry one, should cost around $30 max. In addition to the rebuild kit you may need to replace the throttle bushings, choke coil, choke pulloff and maybe the throttle position sensor. You can order those parts separately if you find you need them. Count on having to epoxy the well plugs while you've got it apart, JB Weld works fine.

If you need some pointers for the rebuild let me know. There's a few set screws that should be counted 'turns out' before being removed so that they can be reinstalled in the original position.