My son has a 94 Trans Am that has been wrecked. He would like to know if he can transplant the LT1 and MN6 out of the TA into his 1980 Corvette. I see a sticky about LS1 installations but not sure if that applies to the LT1. Can someone please point me in the right direction?

 

There are a number of people on the forum who have put a LT1 into a C3 but there isn't an organized thread about it. Aside from adding an electric fuel pump and wiring in the ECM the rest of the installation should be pretty straightforward.

If you look on ls1tech.com I think there is information about LT1 swaps also.



Rick B.

 

Thanks for the info.

 

Also take a look at thirdgen.com(Camaro website)

 

I also mess with Jeeps/rockcrawling and a lot of guys put the LT 1s in their rigs. Biggest issues are cooling, power steering pump and transmission cooling. If you are running a manual, no issue, however, if you have an automatic, you should probably run a cooler for that too. The LT1 and later motors like to run at 210 or so, and the 200r4/700r4 don't like it that hot. They can take it if they have been beefed up, but a cooler helps the life expectancy. Not sure about turbo 350/400 trannys. Most of the guys I know run electric taurus fans to keep em cool. All of that I have seen run like a demon. Good luck. The Pirate 4x4 web site has a ton on lt1 installs if you need more info on the general ecu set up etc. Oh, and most use an aftermarket, stand alone, wiring harness from Howell or Painless. A little more $, but I hear it is well worth the investment, especially if you have any issues. Easy to trace/troubleshoot.

 

Motor mounts should be in the same place. If you use the T56 the tail will sit right over the crossmember. You'll need to cut a hole in the floor for the shifter and shorten the driveshaft.

 

Mainly for TPI but has LT1 info at the end.
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You have a unit
First you have to determine whether you want mass air flow or speed density. The C3 is more conducive to speed-density due to space issues. Mass-air flow is easier to make engine changes without PROM changes. If you are technically proficient enough to make a Camaro harness work they can be bought for $100 or less. I have been told that you can also use a 3.1 Corsica or Cavailier harness with a little work, it uses the same 7730 Speed-Density ECM. Aftermarket harnesses range from about $300 for Painless to $500 for Howell to $700 for Street and Performance. Howell makes a great harness, but for a Tuned Port they do not make one that will control the converter lockup on a 200R4/700R4/4L60 transmission. If you are running a manual or non-overdrive-automatic transmission I highly recommend them. I have heard great things about Street and Performance harness, but do not have first hand experience with them. I also have a Fuel Injection Specialties (FIS) harness and it is OK. The ECM can be had used for $10-50. A good external fuel pump will cost at least $100. I use an 88 Ford Truck external pump, $114 from CarQuest, made in Texas by Airtech (also available at O'Reileys). If you have a 78-82 you can use your fuel tank with an 82 sending unit and a TPI pump. 68-77 can also use a modified tank or Rock Valley makes a tank for these cars with a baffle and a GM internal fuel pump. Stock 82 tanks do not have a baffle contrary to popular belief. An aftermarket PROM with VATS and Emissions codes removed will be $100-200 depending on source and complexity. You will have to add an oxygen sensor to your exhaust, $20 for the sensor, $5 for the weld-in bung, and say $25 for an exhaust shop to weld it in if you can’t. Some harnesses use VSS and some do not. An auxiliary VSS sensor is around $75. I recommend using VSS to get better drivability. To install a TPI I say figure at least $800 plus the TPI unit and whatever repairs are necessary to bring it up to useable status. I have TPI/700R4 in my 69 Corvette (Howell harness) and an 83 Pickup (FIS harness) and I love it. Starts good, great torque, good fuel mileage, easy to swap onto stock engines (although both of mine are complete engines out of 90/91 ‘Vettes).

Differences in years
All Corvette TPI intake manifolds work with the older (through 86) iron heads and the factory aluminum heads through 91. F-body TPI intakes use the upright center bolts on 87-92 and thus fit all 87-95 iron heads (non LT1). Either can be swapped to fit the other with some drilling. F-body has the fuel lines come out on the drivers side and has a central port for EGR. Corvette has fuel lines that come out on the passenger side and has an external port for EGR. Corvette fuel rails fit F-body intakes and vise-versa. The runners are all the same through the years, but the LH runner has a hole for a 9th injector in the 85-88 runners. This can be plugged off if you get a nice LH runner and don’t want the 9th injector or decide to run speed-density. The plenums all physically interchange, but 90-92 have an extra vacuum port for the MAP sensor used with the speed-density computers and wiring. 89 is an odd year, it is mass-air flow but without the 9th injector. 89 up throttle bodies can be used on all years, but a 85-88 throttle body requires a ½” hole be drilled in the front of a 89-92 Plenum for idle air. 89-92 Throttle bodies have a more desirable cable attachment. The cable attaches around a circular linkage which has a smoother actuation than the straight linkage on the 85-88. The Corvettes have an aluminum plenum extension over the distributor, the F-body extensions are plastic. The Corvettes use an HEI coil-in-cap distributor for 85-91 (Delco 1103680). 85-86 F-body also used a big-cap distributor. 87-92 F-Body used a small cap distributor with an external coil (Delco 1103479). This same distributor is used in the 87-95 5.0/5.7/7.4 TBI injected trucks and pre-LT1 B-body. The F-body intake gets it's exhaust for EGR from the center passages in the heads like most SB Chevys. A Corvette intake gets it's EGR exhaust from the RH exhaust manifold/header through a flex-tube to an opening near the distributor-no center passages in the intake. If you are required to keep EGR and you have a Corvette intake, I recommend getting the C4 exhaust manifolds. They are like mini-headers, and have a 2 1/2" outlet. I have them on my 69 and like them.

As far as a throttle cable to use, on my Vette, I used a TPI Corvette cable, 1990 I think (now discontinued from GM) but you have to cut the end off inside the car and use a hood-release-cable end (Corvette Central 342138 "cable stop") to get it the correct cable length (the housing is OK). You must use a cable from the type car your throttle body came from if you want to have a chance of not cutting it. Again, 85-88 use a straight pull, while 89-92 have a circular attachment for more smooth actuation and so the inner cable is longer. On my 83 truck I used a TPI F-Body cable and it was OK, but I had to coil it up into a loop in the engine compartment because the housing was so long. I also TPI'd a 72 Chevy truck and used a 90 350 TBI truck cable for it. It was 1/2" short outside if anything, but I was pretty pleased with it all told-I didn't have to shorten it. In a Vette it might be about right. In all vehicles I've done you need a die grinder to square the firewall hole off a bit. All vehicles I've done used the late throttle-body.

I would look into a TPI. They start immediately in winter, have great vacuum, and will get great mileage. I can open the headlights and the wiper door at the same time with no hesitation at all-solid wooomp. With 3.70 gears (and a 700R4 overdrive) I get 18mpg city and 22+ highway. With 3.55 or 3.36 it would be even better. You can probably find a used Corvette TPI engine for $1000 and with an $800 harness/computer/fuel pump you would be set. On a 78-82 you can use the stock fuel tank with an 82 sending unit and TPI pump and be in better shape than 68-77 with an external pump. With the Vette TPI you would have aluminum heads that would remove weight. Even with an F-body iron-head TPI 350 it will be less weight than a stock intake. It will bolt up to everything in your car, use stock accessories, use your transmission, and the visual appeal is awesome. Don't be afraid of fuel injection, it really works.

As far as websites see:
www.corvettefaq.com for conversions or more TPI info at www.fuelinjection.com also www.jagsthatrun.com for misc hard to find conversion parts and info.

LT1
Not to get too deep into the differences in LT1s, there are basically 3 variations. There is the C4 ('92-96) and an F-body ('93-97) version which are 5.7L and have aluminum heads. There is a B-body ('94-96) which is 5.7L with iron heads that actually flow better than stock aluminum heads. There is also a 4.3L B-body (L99) version that you want to stay away from. There is an LT4 in '96 that is an upgraded LT1. All are dimensionally the same as far as bolt-ons. Corvette engines have 4-bolt mains, all others have 2-bolt. All are cast iron blocks. An LT1 is a very similar installation to a TPI. As far as the mechanical installation, the 700R4 and 4L60E transmissions are the same (same length, same basic dimension, mounting, yoke, etc.). You have to have a computer to run a 4L60E which you will have for the engine anyway. As far as the engine, an LT1 will bolt in and can use the same exhaust although you may want to use C4 LT1 manifolds to get true 2 1/2" outlets. The biggest difference between a TPI and an LT1 installation is accessories. TPI can use stock C3 accessories. LT1 has to use LT1 accessories and really needs C4 LT1 accessories. Both F-body and B-body put the a/c compressor low on the passenger side. This interferes with the frame and the right motor mount. You have to use electric fans on an LT1, there are no provisions for a mechanical fan (B-body has an optional one, but it is offset and won't work in a C3). The other difference is in air intake, most LT1s are mass air flow. Again, it is difficult to locate the MAF sensor in a C3. You are better to have it set up for speed-density. In a '78-'82 C3 you could still use an '82 sending unit but an LT1 fuel pump instead. You will want to stay with programming for an OBD1 (pre-'96) style setup, without multiple oxygen sensors. '96-'97 OBD2 engines are fine, you just don't use all the sensors. LT1 requires a custom radiator because of how the hoses run. There are differences in the Optispark, later is better and if you swap to a later cam you can add the later vented Optispark setup. The water pumps are bad to fail and wet the Optispark, so always replace the water pump when you do a swap. LT1s have better top end power that TPIs, but all things considered I'd rather stay with TPI for a cruiser or mild build-I just like the look and the low end torque. If you want more power, LT1 is better; or just step up to an LSx.

 

Thanks a lot for the great info, I've forwarded it on to my son.

 

I have successfully installed a LT1 in an 81 corvette and it is smog legal in California. I'm currently trying to figure out how to post the 52 page document that I wrote on my lessons learned.

 

!
Post it brother!!! we want to see it


PS... i have seen the final install and it is way made me jealous!!

 

 

My mechanic who helped with the install, Halls Automotive, is going to post the Lessons Learned Document on his website. I should have a link to it by September 17th.

 

Plan on doing the same project. Have a 96 LT-1 out of a 96

 

Hey Guys, sorry for the delay of posting the document but i'm at the mercy of someone else but he assures me it will be available soon. However, one of the members here sent me an email and although the doc is pretty large,(20mb) I was able to send over email. So if any of you out there don't feel like waiting another week, just email me and I will send over email. Put 81 Icon in the subject line so i know its not junk mail.

 

You are going to need the C4 brackets and accessories. I'll be pulling the engine out of my '94 tomorrow, and I will have the accessory bracket, alternator, and power steering pump available to sell. You will also need the C4 balancer as the F-body balancer places the belt at a different depth. I have a stock C4 LT1 balancer, and an ATI C4 LT1 balancer available. PM me if interested.

 

It was hard to find but that's why I went with a corvette motor vice an F body. I had heard that there are certain nuances, albeit not insurmountable, that must be dealt with. A corvette LT1 drops right in.

 

Here is the link guys. The lessons learned is at the top all the way to the right. Still working out the bugs

http://www.hallsautoinc.com/Corvette_Blog.html

 

Wow! Impressive.

 

could you email it to me mkennard1@tampabay.rr.com

 

I just got back in town. Emailing it now. Its a big file so get it out of your inbox ASAP