Hey all,

I was just looking around on the internet regarding swapping efi onto a SB. I was just wondering what anyone else has done. Have you just swapped a whole efi engine in?

Will TPI heads and induction bolt onto an older block or is it not that simple.

Thanks,

cosmicvette

 

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. If you have a 78-82 you can use your fuel tank with an 82 sending unit and a TPI pump. 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. 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 bit 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. 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 (about $20 new 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.

Why to get it
If all you want is around 300 hp there is no reason to spend a pile of money on a crate motor. The basic $1200 4-bolt Goodwrench 350 with an aluminum intake and a Holley will put out power in that neighborhood. Chevy High Performance (I think) did a series of articles with one of those a few years back and with decent exhaust should get you in that range.

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

 

Yes the tpi will bolt onto a older block,i have a 87 t/a setup on my world products heads,just have to drill out the center intake bolt holes,no big deal.There are a few guys on here that have swapped over and a few more in the middle of a the swap.If you search around and find the partys cheap it can be an inexpensive way to get into fuel injection.Check out this website for info.Mark covered it pretty good.

http://chevythunder.com/speed%20dens...n%20manual.htm

 

Thanks for the replies guys.

That definately gives me something to think about.

Now I have to start loking for the parts. I think I may keep an eye out for a complete engine/trans setup.

cosmicvette

 

Good link here. I am thinking of going with these guys.

http://www.affordable-fuel-injection.com/index.htm

 

Here's another link:

www.firstinjections.com

I think he sells his manifold and plenum combos to other distributors as well. The pic of the TPI unit at the affordable injection site is (if I am not mistaken), the setup I got from Ken and now in my car. It looks like the pic Ken took of mine for advertising. It is a great system.

 

A number of us have swapped aftermarket EFI units (Holley, etc.) onto our engines also.

 

I was checking out the AFI website...The system at Affordable..FI is the same as Ken's. Without saying how much, I think you can get a better deal with Ken, as he IS the distributor and holds the patent to the FIRST unit.

 

Here's a pretty good FAQ on TPI:
http://www.classictrucksweb.com/tech/0404cl_tpi/#

 

i am in the middle of my project which includes an edelbrock pro-flo EFI kit and so far the only problem that i ran into was the wiring. the hardest part of this project is finding a spot to route the wires through and into the passanger compartment. after months of trying to figure this out and with tons of help from others on this forum i think have found the bast way to go about doing this without cutting and holes in the firewall. a while back someone on here metioned that there is a hole just under and to the driverside of the brake booster that isnt used on automatics and sure enough there it was but when i tried to route my wires to it they came up about two feet short sense they were ment to be routed through the fire wall on the passanger side but i have a solution for that. i pulled out all my old wiring and i am replacing it with all new wiring and found taht the A/C harness passes through the fire wall right where i need to pass the FI harness through so now i just need to make my A/C harness 5 feet longer and route it through the hole next to the brake booster and now my problem is solved sorry bout the long reply and GL

 

Good info. I like the bigger runners since I don't think a stock TPI will feed my 400HP motor. Of course, I need more $$$ in the bank first.

 

If you have a 68-74 and are converting to an electronic tach, you can use the tach-cable hole.

 

Thanks for replying everyone. Now I have heaps of info and websites to ponder over.

Cheers,

cosmicvette