MrMoustache

I am going to swap the tired old 305(carb) out of my Firebird and replace it with the 350(TPI) out of my rusted out Trans Am. The body on the Firebird is rust free and the Trans Am body is rusted through the floor pans, both front corners and the spare tire well. This is all the rust I feel like finding and I am giving up on the Trans Am body.

I was wondering what type of problems I may run into swapping out the engines. I have both complete cars nearly ready to start the swap. I am also looking for a set of aluminum heads to go on the 350. (The Firebird is my daily driver until this weekend when I can find something better to commute in, 226,000 miles on the 305 and the expense of gas are getting to be too much for me right now.)

Any help, suggestions, or advice would be greatly appreciated. Thank you!

PA91Z28

As far as bolting it in it will fit no problems. But you will need to swap over the wiring and ECM since your old 305 has a carb on it and the 350 has TPI.

MrMoustache

Thanks! As soon as I get a new vehicle I am going to start the process. I will be documenting throughout this post and in pictures to help everyone else along if they wish to attempt it themselves.

thomas1976

Sounds straight forward, if you can use all the parts from the donor car, don't forget the fuel pump and compare the fuel lines.

MrMoustache

It has been a long time but I am about to move the cars into a covered area to finally begin the swap. I will try to post pics each day I work on the cars to help others as well as myself as i try to put the thing back together.

sofakingdom

iTrader: (1)

Or, you can put the whole carb setup off the LG4, onto the 350.

Just make sure to use the 350 exhaust, not the LG4 crap.

MrMoustache

What benefit would I get by retaining the carb instead of switching to the tpi setup?

sofakingdom

iTrader: (1)

Mostly, a whole lot less work and more power. At the expense (potentially) of fuel economy and emissions.

MrMoustache

Are you talking about using the LG4 carb as well or an aftermarket carb?

five7kid

iTrader: (14)

USE THE LG4 CARB!

An aftermarket carb is a waste of money, requires more work to install (might was well convert to TPI), reduces fuel economy, doesn't improve power, and won't pass emissions.

89RESTO

iTrader: (5)

If your going to switch the carb. set up to the tpi motor make sure the heads have the same bolt pattern for the intake.

Guest

Agreed. Mostly. Plus the aftermarket carb probably won't give the driveability of the TPI. And the aftermarket carb will end up being rich all summer, then lean all winter.
However, a non-computer QJ can give better MPG than anything computerized. Because all the computer options have to run at 14.7:1 air:fuel, while going retro, you can cruise at 17:1. Not good for emissions, but can really help MPG.

MrMoustache

Will I have to do anything to the computer for the LG4 if I swap it onto a bigger engine (350)?

Guest

When GM did the legal 350 conversion, all they changed was the secondary metering rods, and the hanger for them. The idle and primary metering changes were done in the PROM chip. Or the Cal-pak. However all that stuff works. IDK.

five7kid

iTrader: (14)

They actually included a chip in the kit if you had an LG4, but when I was running my ZZ4 clone with an '86 LG4 system, it was quite happy with the factory chip. Using the kit chip actually made it so you had to use premium gasoline, with the more aggressive timing tables it had. I typically just ran regular unleaded (switched to mid-grade when racing).

MrMoustache

Well first off I had an adventure last night moving one car to the swap location. I was using a tow dolly to move it and got about five miles down the road when a tire on the dolly blew out. Wasted about four hours of my evening trying to take care of the situation. All is well now though but if anyone decides to borrow a neighbors car dolly make sure you put new tires on first.

I think I will try the swap using the LG4 carb setup first but I will hold on to the TPI setup for a while in case I want to convert it. That being said, does anyone know where i can get a good rebuild kid for the LG4 carb? I want to make sure it all runs right when I get everything together

five7kid

iTrader: (14)

I got the kit for mine from Checker (now O'Reilly). Anything you get from any chain parts store should be fine.

lonesomeloser

I bought my rebuild kit here: http://www.cliffshighperformance.com/index.html

BLKIROCZ87

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MrMoustache

Did you get the HP or the SR kit?

lonesomeloser

Electronic kits are only available in the HP kit.

MrMoustache

I'm finally in my workspace and getting everything ready to do the swap. Here are the cars together and pictures of the engine bays with the engine from the black Trans Am about to go into the blue Firebird.

MrMoustache

A lot has happened to the Firebird recently. I just haven't had time to upload pictures and make updates to the thread. I will get to this as soon as possible to let everyone know how the progress is going. This would go faster if I actually had someone helping me do this but as of now the only help I have been able to get is my girlfriend hanging out with me in the shop handing me a wrench occasionally.

BLKIROCZ87

So did you go with the LG4 carb? i have a 89 vette motor going into my LG4 Iroc and cant make up my mind on which way to go... Like to see some pics when u get to them.

MrMoustache

I still plan on going with the LG4 carb but the engine is not in yet. It probably won't go in till the beginning of September but I will let you know how it goes then.