I’ve got a 91 Camaro RS with a 305tbi and a 700R4.

The idea has always been to LS swap it, but it is pretty intimidating, not going to lie. The SBC swap seems so simple in comparison.

With the SBC, I won’t need to drop the fuel tank and do a fuel pump/new lines, no computer wire up, no need for a tuner. Id just keep the 700r4 as well. Drop it in and adjust the carb.

Then I saw some videos of carbed LSs. Can I have my cake and eat it too? Would getting a junkyard 5.3/6.0 and slapping a carb and dual plane intake allow me to avoid the most problematic part of the swap?

I’m not too concerned with gas mileage or carb tuning(this is my project/weekend car). Not looking for big HP, I’d love to eventually hit 300wheel.

Am I missing something glaring? Or would something like this work for my situation?

 

Honestly I feel like if you're going through the hassle of an LS swap, might as well go all the way with EFI. The aftermarket kit's they have these days make it a breeze, most self tune which get you running decently enough until you can get it over to a real tuner. They also make it pretty fool proof with premade wiring harnesses and tons of online support (especially holley efi systems) dropping the tank and new lines (do you really need all new lines for 60psi and 300 wheel hp?) is a drop in the bucket compared to the rest of the swap imo

 

I agree, both Holley and edelbrock make easy to use systems. I think running new lines will be helpful as far as fuel pressure regulator return. I had issues w premature fuel pump wear/heat. I think it was due to using the stock size return line. Now I have a 6an feed/return and things seem to be happier. But people seem to do OK w the stock return. Either way, efi is the move. The hard part of the swap isn't the fuel system and hooking up a standalone efi is easy.


also, a LS style front mount intake will fit under the stock hood. A carb w air filter may not.

 

good points. I rewatched a video on dropping the tank. It’s really not so bad. There was this small part of me that was curious about doing something a little different with the carb, but it’s probably not worth it in the long run.

 

lets start at the beginning

it bolts in the same as the SBC
it uses the same transmission as the SBC
uses the same wiring and radiator as the SBC

so which part is intimidating? Also, there is step by step how tos in here, the internet, and if you get stumped just ask a question like you are now.

and as far as carbs go, carbs are for food not engines. You can take a $400 ls engine and put it in your camaro and have it running and driving for under $3k. Start a build thread, ask your questions, document them, and get to starting your swap..

There is ZERO reason to be intimidated by a over 20 year old engine.

 

Carburetor only eliminates the fuel injectors. You'll still need the ECM and all the engine wiring for coils and sensors.

Your takeout engine already has a tune in the ECM, just don't mess with things and you're good.

 

LS carb swaps are very popular. Particularly among the drag racing crowd.
A stand alone ignition controller is all that's needed.
And the ability to tune it.

https://www.holley.com/blog/post/msd...arburetor_too/

Should my retirement days play out as expected I may go this route too as I've got most of the main players waiting on the sidelines. A very nice condition early Berlinetta (without the digital dash) and a solid running 06 Tahoe with a 5.3 that'll eventually be parted out.

 

In my experience, the only thing carb does better than front-mount TB EFI is nitrous.

If you ain't spraying, you might as well do EFI. There are a lot of options out there.

Oh, my 3rd gen EFI LS1 pulled 350 HP. At the wheels. At altitude. It did have an aftermarket cam, though.

 

Carburetor makes more power. The evaporation of fuel in the wet flow lowers the inlet air temp resulting in a more dense air charge. But the kind of intake you would need won't fit under a stock hood, and that's where the EFI intake shines.

 

If you do plan on going EFI get a system that has not only a huge support system but also tuners will tune them.

Also don't be fooled by the "self tuning" mumbo jumbo it is very much not self tuning. The base tunes that come with most systems are just that "base tunes" they'll get you up and running. But they need to be tuned.

You never want to rely on closed loop/learn to get your fueling right and then there's the timing that needs to be addressed. With any aftermarket EFI system you'll need to verify the timing on the engine so everything matches.

 

I once used play-doh to measure my hood clearance. The room for a carb with a stock hood just isn't there. Out of curiosity, I googled lsx offset manifold carburetor, and it does exist. Maybe a Holley single plane manifold, an Offenhauser Carburetor Adapter, and a little ingenuity might work with the Trans Am power bulge hood. I'm happy with my EFI. Keeping the early thirdgen look under the hood would have been cool, though.

https://www.summitracing.com/parts/OFY-5497

 

I don't really think it'll be 'easier' than EFI, just different, and with different headaches. We did an LS swap on our C Prepared Firebird. I figured I'd be frugal and use the carb that was on the 305 and a distributor, saving some parts buying. A distributor will require a Wegner front drive kit, which is NOT cheap. It also uses a Ford-type distributor, since it's front-mounted, so really no savings in the parts list.

After we got the car back together, we discovered that the carburetor was so worn out, it was leaking, both air and fuel, badly, and just really needed replacing, so no cost savings in the carb department. The car runs GREAT, it's a 310 LS1, but would probably fire and idle smoother with EFI. We're committed now, and have worked out all the kinks, but the road to track-worthy was not smooth.

The Holley single plane does mount the carburetor closer to the engine, but even with that and a drop base on the air filter we needed a 2" cowl hood. We're working now to seal the air filter to the hood so we can get cooler air from the cowl, but that's another project.

 

Looking good! I see you have the elusive Pontiac LS Valve covers. Are those the discontinued covers that GM performance used to make? I wanted those covers for my build. Now I'd have to relocate the ignition coils, so I stopped looking.

 

Yes, they are. I actually sold them here a few months ago. We had to improve our oil control, so I used a pair of tall standard LS covers, not wanting to butcher these. They were really nice covers, and I jumped on them when I discovered them. Alas, we had to go a different route. At some events, we ended up running near redline for extended periods of time, which pushed oil out of the catch can we were using, making a BIG mess. The new system has two cans, one 'catch', one 'breather', with -10 AN hoses from both valve covers to the dirty side 'catch' can.