View Full Version : LSx Carb'd Swap Q's


MiniLSx
12-29-2011, 06:45 PM
Hey guys, I have a 1985 Trans Am 305 TPI. The old 305 is getting a bit tired, and i'm looking into doing an 5.3 swap. Now, I want to do this as simply and quickly as possible. Would a carb'd setup be easier to setup then the fuel injected setup? since the car is fuel injected now, would i need to do anything with the fuel system to make a carb'd system work right? i plan on keeping the original trans (700r4) and everything else. basically, i'm looking to see whats quicker/easier to do. if i were to go the carb'd route, what kind of intake manifolds do you guys recommend?
thanks in advance

ZONES89RS
12-29-2011, 07:24 PM
Check out the lsx/ltx swap section on www.thirdgen.org and look at the EFI swaps they have there, they will give detailed break down on cost for both. Depends on your budget and ability with mechanical ability.

MiniLSx
12-29-2011, 10:22 PM
Cool man thats some good info! I'll be reading it thoroughly :)

NemeSS
12-29-2011, 10:36 PM
Hey Zane
We should have a 3rd gen swap sticky guideline here for a carb version. A breakdown of parts cost and typical of what can be done with basic parts and budget.
U alredy know where to get the ls engines :secret2:
I will supply the alternator and other accesory brackets and configurations.
I got a whole new updated version of the alternator bracket.

Paul57
12-29-2011, 10:36 PM
I think your decision is going to depend a lot on how much electronics you get with the new motor. If you get little to none then a carb will probably be cheaper. If you are planning on keeping the motor stock then factory EFI might be worth keeping. The Edelbrock RPM intake would be enough for a 5.3 unless you are shifting at 6500+.

MiniLSx
12-29-2011, 11:52 PM
The engine would be mostly stock for a while, internally. Im sure a stock 5.3 probabaly has twice the power of the 305 as it sits. But eventually i'd like to tear into the engine

MiniLSx
12-30-2011, 12:48 PM
also, i'd probably be getting just the engine. not likely to get the harness/pcm with it. so in that case, carb swap might be cheaper/easier? i'm not looking to make an insane amount of power or anything right now, this is just going to my street machine. i hear you guys talking about a module that controls the coils and stuff, so i'm gonna have to look into that further.

newschool72
12-30-2011, 02:21 PM
An MSD box (6010 or 6012 depending on your reluctor wheel) will control the spark and timing. I think with the factory fuel pump in the tank, there will be way too much fuel pressure for a carbed set-up. Im not sure how a pressure regulator would work with the high pressure of the EFI pump.

speedtigger
12-30-2011, 03:50 PM
Any of the carburetor return style regulators should work with his high pressure fuel pump just fine. You just can't dead head it.

Paul57
12-30-2011, 03:55 PM
An MSD box (6010 or 6012 depending on your reluctor wheel) will control the spark and timing.
Like he said, make sure you get the MSD box and not the Edelbrock. You will have to buy the intake and box separate. The MSD box is programmable while the Edelbrock is not.

ZONES89RS
12-30-2011, 05:43 PM
Hey Zane
We should have a 3rd gen swap sticky guideline here for a carb version. A breakdown of parts cost and typical of what can be done with basic parts and budget.
U alredy know where to get the ls engines :secret2:
I will supply the alternator and other accesory brackets and configurations.
I got a whole new updated version of the alternator bracket.



Actually I dida pretty thorough detailed swap price for a budget genIII/IV swap on TGO, I might copy and paste it here and modify it a bit. I will get with you on it when I have time.

NemeSS
12-30-2011, 10:22 PM
Ok. Cool. I dont visit tgo that often anymore