OBS rcsb TBI to LT1 swap

[g9m3c]

Just bought the donor car 4 days ago. It's a 1997 Formula Firebird with the LT1/4L60E and 120,000 miles on it. Keep in mind that this will also be an OBD1 to OBD2 swap as well. Right now the plans for the engine are just to rebuild it, gasket match the intake and heads, throw a nice cam in it (undecided on which one......need suggestions), a 52mm throttle body, and a pcm tune. It will also have all the proper bolt ons: LT's with a true dual exhaust, custom cold air intake, msd coil, nice plug wires, etc. etc. I also already have electric fans, so that's one project I won't have to worry about. I will probably opt for some other mods on down the road, but for now, I'm trying to keep the expenses as low as possible. The throttle body was damaged during the wreck, so I've already taken it off and got the stuff off of it that I need. I've started taking stuff loose and out of the engine compartment in preparation for taking the engine/trans out. I'm a little overwhelmed with the wiring at this point though. I'm just labeling everything I take off and hope to sort it out after I get it out and can take a good look at it all. I'll try to get some pics up in the next day or so because I only have the one I took with my cell phone the day I got it.



Does anyone know what the computer under the passenger side frame rail at the front of the engine compartment would be for? It's about half the size of the pcm and is aluminum. It's right near all the smog stuff, so I'm hoping it has something to do with that and can be eliminated. I was just hoping someone knew what it was to solve my curiosity before I tear into the harnesses and figure it out.


I am planning to type a very in depth guide to the swap as I go along. I am positive it is going to teach me a lot, because it is very overwhelming at this point. I hope to pass that knowledge onto fellow FSC'ers.

[tatoodkelt]

I will definitely be following this. My dad has an LT1 from his 92 Vette sitting in the garage. I was thinking about finding it a new home.

[Black90Sport]

tatoodkelt you should sell it to me. looks awesome ill probably b following you in this move come next winter. ill b watching make sure you document it all really well so its easy for me hahaha.

[g9m3c]

Originally Posted by 81chevyc10

tatoodkelt you should sell it to me. looks awesome ill probably b following you in this move come next winter. ill b watching make sure you document it all really well so its easy for me hahaha.

I always gotta spell it out for ya don't I???

[IH8FORD]

this is awesome i cant wait to see more progress

[Black90Sport]

Originally Posted by g9m3c

I always gotta spell it out for ya don't I???

not always but most the time yes.

[g9m3c]

Originally Posted by 81chevyc10

Originally Posted by IH8FORD

this is awesome i cant wait to see more progress

Me too!

[CemeteryRoad]

I'm in the process of swapping an LT1 into my Blazer right now. What are you doing about the wiring? I've got my harness laying on the floor right now, scratching my head trying to figure out what wires to cut

[CemeteryRoad]

On a side note, Why are using OBD2? You are switching the cam so you are going to have to tune the ecu anyways. Why not just switch to an OBD1 ecu and not worry about what the bcm controls

Just a thought...

[tatoodkelt]

Originally Posted by 81chevyc10

tatoodkelt you should sell it to me. looks awesome ill probably b following you in this move come next winter. ill b watching make sure you document it all really well so its easy for me hahaha.

Nice try, lol. I meant find it a new home in one of my trucks!

It's just the motor though so I would need to find a wiring harness for it still.

[g9m3c]

Originally Posted by CemeteryRoad

On a side note, Why are using OBD2? You are switching the cam so you are going to have to tune the ecu anyways. Why not just switch to an OBD1 ecu and not worry about what the bcm controls

Just a thought...

Because the car that the engine and trans are in right now is OBD2. Plus, I haven't seen an OBD2 LT1 swap, so I plan on taking the challenge.

[91blkstpsd]

I'm in the process of swapping an LT1 into my Blazer right now. What are you doing about the wiring? I've got my harness laying on the floor right now, scratching my head trying to figure out what wires to cut

The wiring isnt as bad as it looks. I felt the same way starting out. One thing that should help is to label all connections then once you have you engine in the vehicle, start laying on the harness and plugging in everything you will use. Once this is done you can start pulling wires that you wont need. ie EGR, smog, etc. To tap into your vehicles harness you will need to locate a few main wires. Fuel pump prime, alt turn on, and a few powers. Also I took the factory distribution block on the firewall and cut it in half. Label one side as B+(constant 12v) and the other side as Switched. This is where you will run all your power wires to. Ill post some pics of what Im talking about. Anyways, Im getting carrried away. haha Here is you a start. Good luck

[g9m3c]

Just placed my first parts order for the beast. 52mm throttle body, spark plugs, and an LT1 overhaul spec book. Gotta start somewhere, right? I'm gunna be going over to the shop to work on it again tomorrow. I should be able to get some of the wiring figured out, and I'm cutting off the front section of the car to make it easier to pull the motor. The body's total trash anyway. I'll be sure to get some good pics of the progress.

[Black90Sport]

hey man seems i might b following sooner then later... but i probably wont even start buyin parts or makin plans til late summer.

[91blkstpsd]

Hey man, just a tip to help on the budget thing. Check ebay for good used parts. I got my 52mm TB ,LT4 HOTCAM,ac delete pulley, and some other various parts. Just make sure to check them out thoroughly first. Parts like these dont wear out easily.

And to answer your PM, I ditched all the EGR, smog, and emissions junk. I live in TN, who cares about HP robbing emissions! lol

[CemeteryRoad]

Originally Posted by g9m3c

Plus, I haven't seen an OBD2 LT1 swap, so I plan on taking the challenge.

Good enough reason for me. Have fun with your swap.

[CemeteryRoad]

Originally Posted by 91blkstpsd

The wiring isnt as bad as it looks.

I can see that now. I labeled most of the wires and she doesn't look so bad now. Tomorrow I'm just going to lay out the wiring in teh truck and see where I get stuck.

[g9m3c]

Originally Posted by 91blkstpsd

Hey man, just a tip to help on the budget thing. Check ebay for good used parts. I got my 52mm TB ,LT4 HOTCAM,ac delete pulley, and some other various parts. Just make sure to check them out thoroughly first. Parts like these dont wear out easily.

And to answer your PM, I ditched all the EGR, smog, and emissions junk. I live in TN, who cares about HP robbing emissions! lol

Alabama's the same way......screw it.

[91blkstpsd]

I can see that now. I labeled most of the wires and she doesn't look so bad now. Tomorrow I'm just going to lay out the wiring in the truck and see where I get stuck.

.
Like I was tellin g9m3c that you should check out www.shbox.com for all the wiring schematics and pin outs. They are an excellent source of help on there. Also shows tech, how-tos, and locations of all components and wiring.

[g9m3c]

I'm going to take some pics of all the various sensors, switches, (whatever the heck they are), that connect to the bagillion vacuum hoses all over the engine. Hopefully some of you can help me figure out what they all are and if I need to keep or get rid of them. If I can get all that crap out of the way, then everything will be SO much simpler, cleaner, and overall better in the end. In the tune, so far I'm definitely going to be deleting the VATS, rear o2's, EGR, AIR, EVAP(I think?), and whatever it needs to delete the cats too. Plus the changes for all my mods. Anything else you think I might need to do with it? I'm going to use the Trifecta Performance GT tuner deal; they're sponsors of this site as well as ls1lt1.