going from injected to carburated, need help.

Im interested in going to a carb set up. I;m looking for the pros and cons, ups and downs. I'd be happy to lost the computer and all of the tuning headaches. No wires everywhere too.

Im looking for a good setup. Whats a good carb for my set up and lower intake, what cfm. Im new to carbs but am sick of fuel injected. I have a 190 fuel pump, what do I have to do in this area.

I totaled out my car buy deciding to get behind the wheel while intoxicacted, the drive train is fine and I picked up a 93 gt off a buddy for 3K, mint too. So I am going trough the system now and what to do some changes.

Thanks for all the help.
 
A few years ago I switched from FI to carb. My setup is a Holley HP series 650 carb, and Edelbrock RPM Air Gap intake, a Holley Black Pump with an Aeromotive Regulator. I love this combo. Each time out the car gets quicker. Oh, and it sure is nice not having all those wires and crap in the engine bay. Good luck with whatever you decide.
 
How do I determine the fuel volume I need? Correct me if Im wrong but the pressure is dictated my the carb, right?

I was looking at the Holley street avenger and Berry Grant, what grant is a nice set up for my 347.

Is there a pump w/ a build in regulator?, and what do I need to do with my fuel pump in the car now?

Any info is much apprectiated.
 
I would have stuck with the FI were I you. EFI's are trouble free once you get them set up. Carbs are always finicky and are dependant on temperature and elevation to perform, not to mention don’t get anywhere near as good of fuel economy as the EFI cars.. Your choice, but it would have been cheaper and more practical for you to just work the bugs out of your EFI set up.

Have fun with it either way. :)
 
Gearbanger 101 said:
I would have stuck with the FI were I you. EFI's are trouble free once you get them set up. Carbs are always finicky and are dependant on temperature and elevation to perform, not to mention don’t get anywhere near as good of fuel economy as the EFI cars.. Your choice, but it would have been cheaper and more practical for you to just work the bugs out of your EFI set up.

Have fun with it either way. :)
My carbed 83 got just as good of gas mileage as my stock 90. And the 83 was highly modded. Granted... If I put my foot in it, you could watch the gas gauge go down lol. If you are on an NRHA tour, then yes... elevation changes will screw the jetting up... but I don't suspenct this guy will be doing that.
 
I am in the process of finishing up my EFI to Carb Conversion.. Here's what I did..

Bought a used Edelbrock Performer 28 Intake, new Holley 600 Carb, used Distributor from an '85 GT with the steel gear b/c I have a roller cam motor, and a fuel system kit from summit.. It includes 20' of braided line with a couple fittings, a holley blue and the standard regulator.. I also got a fuel tank insert to replace the old pickup/intank pump assembly..

Here are the Cons of what I did.. Forget the fuel system kit.. The regulator is no good.. you need a bypass.. So I got the Mallory bypass regulator.. The braided line is a PITA and gets expensive with the fittings b/c you dont get enough in the kit.. If I were to do it all over again, I would run aluminum or steel line.. I used aluminum for the return line.. Helluva alot cheaper & faster.. You have to replace the fuel lines b/c they are too small. 5/16" stock.. You need at least 3/8" or bigger, depending on your HP output.. I used -6an, equivalant to 3/8"..

Next, forget the tank insert and have a sump installed on your tank, or get a sumped tank or fuel cell.. The insert has a -10an feed line, or 5/8" feed line.. I needed to go down to -6an.. So after the additional reducers & couplers & line I had to buy and put together to geto down to -6an, I went to install the tank ands the fittings stuck out too far and hit the frame rail. So I had to notch the frame rail behind the quad shock.. I also had to fab up a bracket to mount the pump b/c it needs to be level with, or below the bottom of the fuel tank.. Not a problem if you have a sump..

I'm sure in the end I'll be happy, you live and you learn..so learn from my mistakes if you can.. At least with the fuel system.. DO it right the first time & be done with it..

On a lighter note, I removed all my smog, a/c, engine harness, computer & everything unnecessary.. Got an A/C and smog delete kit, painted the stock pulleys, alternator, p/s pump & brackets & it looks real nice.. Just need a nice electric fan to get rid of the stock clutch fan and I'll be happy..

Good luck and feel free to contact me for any info/advice.

Joe
 
Fletchers writeups have most all the info you need so theres not much I can ad but I will make a couple of comments on fuel and ignition systems. I found when I did my first 4cyl/to carb V8 conversion, this was the area that I found the least usefull information on.

Fuel- There are plenty of options here including sumping your tank or using one of those $100 aftermarket pickup tubes but there are also more buget oriented approaches to this as well. I have done it two ways. If you can find someone parting an older carbed car, you can use the pickup tube from that. It mounts in the same location as your stock EFI pump. Those tanks didnt have the seperate spot for the level sender so it is attached to the pickup tube. I had to remove the float arm to keep it from interfering with the sender in the EFI tank. Do not use the tank from the carbed car because you will create one more headache trying to get your sender to work. Another option I used was to drill a hole in the bottom of the tank and install a fuel cell bulkhead fitting. I installed it in the baffled area of the tank that surrounds the EFI pump. With this method you need to remove the EFI pump and block off the pickup and return lines. I tried to weld the holes shut but found the metal didnt like being welded. You could either braze them shut or go the shadetree route and enlist the help of JB weld.

You have infinate choices in fuel pumps but I like the Holly red or blue pumps because they are affordable and work well. I will caution that they can be a tad noisy. There is no need to run new wires for the pump. You can splice into the factory wiring at the tank and retain the functionality of the inertia switch. Since my cars started life as 4 bangers, I cant give specific wiring instructions. I found a method of powering the pump that requires only a relay and splicing a couple of wires in the kick panel. V8 cars are sure to be different.

I went back and forth thrying to decide what I wanted to do about fuel line. I have used braided line in the past but its very expensive and definately an excercise in patience to assemble. Its also good for making blood squirt out of your fingertips. I have also used aluminum line and it seemed to work well but I have heard alot of poeple report longevity issues with it. What I ended up using is Aeroquip socketless hose. It basically has the same strong points as braided hose but its alot less expensive and very easy to assemble. Even though is is technically rubber hose, its reinforced and I have been told that it will pass tech at the track just as if it were metal or braided line. It does not fall under the 12" of rubber hose rule. -6 should be adequite for most and moderate street car. You also want to install a good filter in the line somewhere. Any little piece of **** will stick oven a needle valve and literally dump fuel into your intake.

Whatever you do, dont use the EFI pump. I know poeple will say they have done it and it works but I believe it to be a very bad idea. Also, dont listen to the poeple that say its OK to mount an electric pump in the engine compartment. I have seen it done way too many times. Mount it as close to the tank as practacle.


Ignition- Again there is the $500 method or the $100 method. I have done both. The $500 method would be to go with something like an MSD billet distributior, MSD control box and aftermarket coil. The $100 method would be to get a rebuilt distributor for an 85 mustang 5.0 with a 5-speed. You could also find a good used one but I found that it didnt cost much if any more to get one from the autoparts store. I paid just over $50 from NAPA. Then you can either use a Duraspark box or what I think is a better method, the GM HEI module conversion. All you need is a 4-pin HEI module that runs about $15, a heatsink of some kind (I used one from an old pentium II) and some wire. You can use pretty much any coil. I used an MSD that I had lying around but I have heard that the stock 5.0 TFI coil works very well with this system. Here is a link to how to wire up the HEI
http://www.bronco.com/pmwiki/pmwiki.php?n=Mods.HomebrewHEI