hey guys, ive started to restore my 88 camaro and one of the things on my list is to do an ls swap with a carb. im either going to be using a truck 5.3 motor or an ls1. the cam i have is mild and ill be using 243 heads off a z06. i purchased the edlebrock intake manifold for it already and the msd 6010 box but im honestly not to intelligent when it comes to carbs. i do plan on putting a plate kit on it down the road. what carbs have you guys used for this swap? if possible please let me know what you use for a carb and possibly your fuel setup thanks in advance!

 

anyone?

 

Like any engine, you just need to choose the style and size (flow capacity) of the carb to match the engine you're putting it on as well as it's intended application (street driver, full-race, somewhere in between).

The carb doesn't know what vintage engine is under it, it only knows airflow.

If it's a street driver or weekend fun car that sees street duty, you can go with something like a Holley 3310 (750 CFM, vacuum secondary). Or a "tuner carb" based on that design. You will never go far wrong with a carb like that.

If you're more into racing or serious street duty, a Holley double pumper (or tuner-carb equivalent) is the hands-down choice. Sizing one properly to the application is more critical than with a vacuum secondary but when you need everything it's got, right now, immediately or it doesn't count, you need a double pumper.

I would love to suggest a properly set-up QJet as the best "in between" choice, but I don't think they make any of the LS carb intakes with a Qjet mounting flange.

 

If the car is strip-only, I could see doing a carb. For street driving, for sure anything that would warrant a q-jet or vacuum secondary, why not just keep it EFI?

 

thanks damon i appreciate the input

5.7, im going car to try something not alot of guys by me have done yet

 

NASCAR's ASA class ran crate GenIII SBC with carburetors so I'm sure there should be some good stuff out there.

Not telling you not to do this but in this instance there is a very good reason not a lot of guys are doing this. The EFI system for a Gen III or Gen IV SBC will deliver more power and be more efficient than any carb'ed Gen III/IV could ever produce. All you are doing by adding the carb is removing the ECM's ability to regulate the fuel delivery. You still need some sort of Ignition Control System since these motors don't have provisions for a distributor.

I haven't done a lot of research on ignition systems for a carb'ed LS1 but the few I've seen were not cheap and rather than having to buy another "controller" I'd just spend my money on the car and software for the EFI system. That's just me.

Still to help you out I agree with Damon. Everyone has their favorite brand carb and most of that is due to familiarity with that style. Pick the style that best matches your application; Street, Street/Strip, Racing.

 

In an attempt to translate that into English, I think that means you want to be different.

Well, you already purchased an intake manifold and ignition system for it. That should tell you that it's a little late to the dance to be "different", since the aftermarket already supports it.

Opening the hood and showing people what's "different" lasts about 30 seconds. You have to live with the effects the other 23 hour, 59 minutes, and 30 seconds of each day. I'll take a car that starts easily, drives effortlessly, spanks the car in the other lane, and gets good fuel economy any day to being "different".

But, it's your car, and your money. Do with them as you like. I'd say a double pumper Holley-type is your best bet for old school carb. By "Holley-type", I mean Holley brand, or Quick Fuel Technology brand, or Proform brand. I'd stay away from Edelbrock carbs. You'll have some tuning to do, which would be greatly aided by a wideband O2 system. To pick the size of carb, multiply your cubic inches by max RPMs, divided by 3456. That will get you in the ballpark. A little bigger if dual plane intake. That formula assumes 100% volumetric efficiency, which you probably won't have, but you'll still be close (at the very least you won't be under-carb'd).

 

check out ls1tech's carbed section. good info over there. i am running a stock 5.3 in my s10 with msd 6010 box and victor jr single plane intake, with a plane jane q-jet. it is a good combo so far. i plan to change some things over the winter though. i originally had a edelbrock 750 mechanical secondaries on it, but it was way too large for the stock engine.

 

For the record, no such thing. All Edelbrock carbs have an air valve in the secondaries.

 

Since he's going carb and has already bought the intake, get an adapter to convert the square bore to spread bore, and put a Qjet on it. The 750 Qjet would be more than enough to run that motor.

As a side note, one of the guys in the car club here has a 78 T/A with an LS1 and a carb on it, it's a Holley 650 with the Edelbrock intake and MSD ignition and Performer RPM intake (all of which Edelbrock sells in a kit minus carb) and it runs like a champ.

 

More efficient, perhaps, but not more power. I doubt the power difference will be very large at all, although Im sure the torque/power curves may be slightly different depending on what EFI intake we're comparing it to.

All a carb does is meter the amount of fuel going into an engine. It may not do it as accurately as EFI in all sitations, but matching the hp of an EFI setup is no more difficult than getting the Air/Fuel ratio correct at WOT.

Perhaps the EFI setups flow more air than the available carb intakes, but Im not really sure on that... But that doesnt mean I endorse going carb with a Gen III, I just dont think "power" is one of the disadvantages of carbs. If you say fuel efficiency, temperament, reliability, hood clearance, Im with you. But power is just not a valid advantage of EFI.

To me the only place for a carb setup on a Gen III motor is if your car is already set up for a carb and you already have a big enough carb. Swapping to an LS powerplant is then just a matter of bolting your carb on top of the LS setup and buying the intake/ignition box instead of having to buy an EFI intake and wiring harness and then the software/hardware to tune the EFI pcm... etc... Staying carb then offers a bit more simplicity and will save a little money and a lot of time. You can always swap to EFI later when budgets allow, and getting the LS power plant is, IMO, the priority.

 

There would be more power in the areas (rpms) where the EFI is more efficient. When I say more power I'm not saying more peak power but more power on average.

I love my carb's and have messed with them since 1983 but you can achieve so much more with the EFI systems now. I've actually considered a 5.3L Gen III/IV for my 70 Z28 but they just don't have the clean muscle look I want when I'm showing it. The original trans and rear end were still with the car but the block was long gone before we got it.

 

these motors like to breath. it'll want something in the 650-750 range. which intake did you buy? please tell me you bought a vic jr and not a performer rpm.

what gear/converter are you running? or are you t56?

 

A carburetor is a calibrated fuel leak