tglennon11

iTrader: (2)

Hey guys,

First off, thank you for all of the information this site has provided. I have only been on a few weeks and have spent countless hours reading up. You all are a wealth of knowledge, and thank you for sharing.

I just bought an 87 Iroc. Its a project. But its clean and pretty straight. The car originally was a 305 TPI with the T5 and t-tops. However two owners ago "blew up" the 305 and decided on a 350 carbed swap. After a while he sold it to the guy I bought it from as a project. Things werent hooked up, gauges for one. This guy did a little work drove it a little bit and then got tired of it.

Now its my turn- the 350 thats in there is burning oil really bad. But aside from that the car runs well. So it needs to get pulled and either rebuilt, or it can get lost somewhere. Hence the post in this section. I am going to take a look at a 94 fleetwood LT1 drop out this weekend. If everything checks out ill be bringing that one home, however as I have been studying up and making my lists etc I am getting more concerned.

The car currently does NOT have the TPI ECM. I have three connectors hanging over the passenger side footwell. It looks like the c100 connector is still relatively intact in the firewalll, but the gauges do not work. I havent dropped the tank, but I am hoping the original fuel pump is still there and just "disabled". There is a mechanical unit on the 350.

So my questions will start with this-

For any LXx (lt1 or i find a LS1) swap, do I use the original TPI ecm at all? Even the gauges/power to the dash.

How much trouble do you guys think Im looking at from what I described?

I really dont want to do stand alone gauges yet, as cool as autometer in a carbonfiber panel would look.

Any words of wisdom would be nice.

And please, before I get slapped for using the t5 behind the stock LT1, this is going to be a daily cruiser. Not a high HP torque monster. Also by going with the LT1, those T56's seem to be more available and cheaper than the ls1 T56. So its in the plan, just not time yet.

five7kid

iTrader: (14)

Welcome aboard thirdgen.org.

Nope, the original ECM won't be needed for either an LT1 swap or an LSx swap. Get what you can with whatever engine you get.

The PCM will have outputs that can feed the factory tach and oil pressure (you can put in a stand-alone oil pressure sending unit if you like).

Voltage comes from the dash, not the ECM or engine.

Fuel level - does that work now?

Speedometer shouldn't change if you use the T5 you have now. Does it work now?

tglennon11

iTrader: (2)

Thanks five7- Thats what I was hoping to hear. I have seen the pinouts for LT1, and I felt better about the tach and oil.

Right now, nothing in the dash works. I checked the cable last night, it seems hooked up in the car, but I plan on being under it this weekend to check out the trans connection- And no the fuel gauge isnt working either.

I am hoping when I pull the engine out a lot of this stuff shakes out when I can see- The C100 wires seem haphazardly draped over the booster.

Brando5641

iTrader: (-1)

How much are you getting this lt1 for?

tglennon11

iTrader: (2)

So the story is- a 100k mile LT1 from a "grandpa driven caddy" the grandson selling it claims it ran great and grandpa was rear ended on the highway.

He wants 450 for the whole thing, engine, accessories, pcm, harness, a full pull out he was going to use on his blazer.

I figure for that I can replace the Opti, and water pump. Add an F-car LT1 radiator and fan set up and be running pretty solid.

five7kid

iTrader: (14)

Don't really need an LT1 radiator.

Are you planning on keeping AC? That produces some challenges.

tglennon11

iTrader: (2)

I figured that I would replace the radiator in there now, I think its an aftermarket one that was swapped in with the 350-

I am planning on keeping the A/C. What issues other than mount clearance will I have? I know to plan on 90 degree fittings and plan to have to massage the k member.

Strick1

I'm in the same position you are in. (putting an LT1 in a 83 Camaro) Here is what I found out so far: If you find a 92-95 Vette, use the A\C mounting from it. It's up top not under. Hopefully, you and I will find a guy that can reprogram our PCMs to remove VATS and what ever else should be done. Power steering shouldn't be too hard to work. But the fuel lines and pump looks like a problem. Let us know what you find out. I, too, am running a thread on this subject.
I'm new to this forum, too.

tglennon11

iTrader: (2)

Well, I ended up with the LT1 and the ENTIRE harness and accessories from a 94 Caddy Fleetwood. 100k miles and the thing is filthy, but it turned by hand pretty good, and even cranking it by hand I was able to get 60-70 psi compression. Which to me was promising. I have started to clean it all up, it will get painted eventually. Ill probably end up dropping it with minimal wiring to see if it works. Then ill re-work the wiring.
Ill probably try to find someone local to program it.
AC wise, well ill get everything in place while the engine is out, but after that Ill wait until the car is up and running before getting the AC to work-
Priority #1 is engine running, id hate to do all this leg work cleaning up the harness, running AC lines, etc etc only to find out the engine wont fire. Or it was a bad motor when i bought it.

Fingers crossed Ill have news in a few weeks.