I'll start this off by saying yes, I've been to thirdgen.org and other sites. Can't seem to find an answer to this specific question.
But first, let's give a brief synopsis of the current situation. I've owned my third gen since 2004, when I was 16. And due to life, marriage, children, divorce, it's been darn near entirely stock that whole time.
Now while browsing Facebook marketplace, I stumbled upon a guy wanting to trade a set of small pattern chevy, 15" wheels, which I happen to have. I'm pretty much getting this thing for free.
It's out of a 1995 Impala SS. 86k miles, car was wrecked and his friend pulled it. Said it had no issues that he was aware of. He was going to carb the engine and ditch the fuel injection, so he has no computer or wiring harness.
Now I know that the b body engines are iron headed, and that's perfectly fine. I also know that existing headers, mounts etc will all work as well. But what's my best source for an ECU and harness? Can I use burn a PROM for my TBI computer, and use to to run the LT1, both are OBD1.
I also plan on reusing the 700r4 that's in the car, and I know that I need certain provisions for that.
It's a pretty common swap so I know it can't be that difficult.
Far as i know, the tbi computer cannot be used on the lt1.
Www.gearheadefi.com
This forum is where i would go.
If it turns out that you can use a tpi setup (7727 ecm and harness) ive got a full setup ill let go cheap to a fellow grm member.
Poke around the junk yard and get a harness and ecu from another car. Maybe you can score a cheap donor car on Craigslist to part out and profit?
Best would be the ecu and harness out of a 95 Caprice, combined with quite a few hours and a good set of wiring diagrams.
Buy an Edelbrock Performer intake and carb and a big cap HEI then time it, tune it and forget about it.
Save the wiring headache for when you decide you want to go LS 
I'm not going LS.
This is mostly due to money reasons. If I wasn't getting the motor so cheap I wouldn't really entertain it.
A used carb setup and a lockup kit for the 700R4 is probably the cheap and easy button here.
In reply to BoostedBrandon:
I'm selling the full TPI setup from my Vette, you're definitely better off and most likely cheaper with a carb/intake/distributor swap.
get an ecm and wiring harness out of another LT1 powered Caprice and throw out all the extra wires to make it into a standalone harness... they integrated the engine harness pretty deeply with the rest of the underhood harness for some reason, so all the headlight wires and what not are in there... not a hard job, just time consuming. i'd go for a 96 ecm and harness, due to the 95 being a goofy "OBD1.5" setup that uses the newer plug but older codes..
other than that, it's a pretty straight forward swap once you swap in a high pressure fuel pump. one of my friends has an 84 Camaro with a Caprice LT1/4L60E in it, and it is pretty damn quick but also smooth and gets 30mpg if driven nicely.
pres589
PowerDork
4/9/17 11:39 a.m.
In reply to QuasiMofo:
Everything I'm reading is that converting a 90's LT1 from FI to carb takes a special intake. Only one I'm finding is a GM Performance intake. Is there some other intake to do this with?
Idle curiosity on my part.
In reply to pres589:
The LT1 heads and cooling are different from a gen 1 SBC so you need the special carb intake or I think you can machine a SBC intake. Unlike putting a carb on a LS they do use a regular old SBC distributor though (you delete the front mount unit).
And the ports line up reasonably well, or is that an issue as well?
What I would do is bung in a crank sensor and cam position sensor and run an LS1 style computer. Get a more modern computer and eliminate the Optispark in one go.
There are bolt up and go kits for this, now.
Yes. The gentleman quoted used an Edelbrock Super Victor intake, Your Mileage May Vary.
In reply to novaderrik:
That's my goal. I was under the impression that my fuel pump could keep up. It's a few years old but I figured if it has a return fuel system the pressure would suffice for an LT1. My car is a 1992.
The TBI will not produce enough fuel pressure for the LT1. But you can change it out for an 89-92 Camaro/FB TPI fuel pump, which fits in place of the TBI pump.
The big benefit of switching to a carb intake is being able to use a normal, stab-in HEI distributor and ditching the awful Opti-spark. You do NOT need a new cam to stab in a distributor, just the intake manifold. LT1 cams still have a gear for driving the oil pump, which is the same gear that drives the distributor.
With the carb intake, you might be able to just bolt on your TBI throttle body, stab in your old distributor, and run your TBI harness/PCM and hope it deals with the higher compression.
OR you can keep the stock LT1 EFI and intake, get a LT1 harness/PCM, and drill a hole in the back for a distributor like so. Your life is better without Opti-spark. Ask anyone.
So my options are:
A.) Find a wiring harness and ECU, get the thing running closest to stock and in the car. This will be the cheapest solution, but the most time consuming.
B1.) Keep the LT1 intake, and convert the ECU and ignition to an LS1 style. This is probably my most expensive option.
B2.) Keep the LT1 intake, but convert to a rear distributor. I've seen guys use HEI and TPI distributors. I still need an ECU, but this is probably the cheapest way to eliminate the Optispark.
C.) Get the $300+ GM Performance Parts carbureted intake, and use an HEI distributor. This has me reworking my fuel system, but is probably the easiest way to get the engine in the car and running.
I need to figure out the balance of time and money.
If you want to go with the tpi setup, ill give you a hell of a deal on a painless haeness, exm, and motorvation chip.
just get all the parts you need to get an LT1 running out of another Caprice, including the fuel pump.. keep the optispark- millions of them were built and drove billions of miles without any problems. just don't drive thru 3 feet of standing water and make sure the vent hoses are hooked up and it's fine..
