[fxa78]

i'm rebuilding a 78 and would like to swap the carb set up to a tpi/tbi. i am using vortec heads on this rebuild. what later model f.i. works on this. i,ve looked at aftermarket and a bit too pricey.

 

[72SBVet]

I know that they make a tpi manifold that will fit the vortec heads. I have a friend in Memphis that has a friend that did this conversion on another car. I can find out what setup he used and what it cost. By the way he used an aftermarket controller to run the tpi as people who burn tpi chips are hard to find at least in my area. The controller is an ls1 ecm modded to run tpi.

 

[sfallison]

One of the Corvette magazines did an article on it..
They used a TPI from a Chevy s10 pickup.

 

[raidmagic]

One of the Corvette magazines did an article on it..
They used a TPI from a Chevy s10 pickup.

S-10's would be TBI Throttle Body Injection.:thumbsup:

 

[D_B]

i'm rebuilding a 78 and would like to swap the carb set up to a tpi/tbi. i am using vortec heads on this rebuild. what later model f.i. works on this. i,ve looked at aftermarket and a bit too pricey.

I've looked into this before, several times, and I explored a lot of options.

What you'll find at the end of all these journeys is that they all cost a lot to do correctly, and they will all cost almost as much as if you just go ahead and buy an after market injection setup that bolts on.

Holley makes a very good system that's very user friendly.

Massflo is another good one that has a lot of applications, is very versatile, and I think is one of the cheaper options.

TBI is the simplest one of them. TPI is cool looking but it runs out of steam at high RPMs. LT1 requires LT1 heads, which require special machining to fit on a standard Gen1 block.

An option that might be easy, is a Vortec injection setup. You're already using the heads. You can get a manifold complete with everything and it'll bolt right onto the engine. You'd need to source a computer and engine harness from a truck or van that had the system stock, and find someone to burn the chip.

I've had a lot of experience with the Vortec 350 engines in the larger SUVs and man they can be tuned to haul ass.

I have a complete Vortec manifold from a 1997 Tahoe. I pulled it off an engine I built for a friend's 1974 Corvette. The manifold is almost complete. PM me if you are interested in going that direction and are interested in the manifold setup.

 

[raidmagic]

Too bad you have the vortex heads I have a complete tpi everything harness all the sensors ecm


The whole 9 yards

 

[fxa78]

thanks for feedback. i guess tbi is the better option for my budget. can i expect good performace with a tbi/votec set-up?

 

[D_B]

thanks for feedback. i guess tbi is the better option for my budget. can i expect good performace with a tbi/votec set-up?

Both systems would get you basic turn key operation.

TBI performance would be less than a carbed engine tuned well, and I think a Vortec injection system would be the better performing option of the three.

The Vortec system has a unique fuel delivery system that directs fuel to each cylinder via a spider-like fuel line. One leg per cylinder.

Here is a picture of my Vortec manifold. It has an iron base, a plastic upper manifold...it's a two piece...and a TB up top.

 

[wd40]

I don't know if the OP made a choice yet or not, but I certainly know that the TBI in my 88 pickup is a great truck motor, but is very slow. I have a TPI in my corvette, that has tons of torque and has plenty of go from about any rpm on the street, and it is true that it looses its luster at high rpm's you would see on a drag strip. But imo it's a great street set-up. I have a 96 pickup with the vortec motor, and I have to agree with D_B, the vortec motor is very stout. I take it to a local drag strip every now and then and surprise alot of people with my bolt-on's vortec. I personally believe in the power a vortec setup can provide.

hope this helps in your decision,
wd40:buhbye:

 

[Slow & Leaky]

Actually....the cost of the aftermarket systems aren't that bad by the time you add up all the bells and whistles that are hidden expenses with a DIY type system.

Here's the biggest question, and the first to ask.

What kind of cam are you running and what kind of power is the motor going to make?

A lot of people forget the cost and hassles that people with OEM fuel injected cars face when building up from stock. So if your cam selection isn't somewhere near stock suddenly the aftermarket systems jump to a healthy cost advantage. These older, swappable OEM systems are fairly dumb and if you have to invest in programming capability to achieve driveability......you're typically rivaling the cost of an aftermarket control system that comes with software.

It's easy to say you're just going to send off ECMs for programming, but old performance cars tend to evolve. Now you need programming for gear changes. Transmission swaps. etc. And you're relying on somebody thru the mail. :down: A guy's just got to own that capability at home, and it's the hidden cost equalizer. First no-start without the capability, you'll be buying the capability.

GM TPI is an awesome system up to around 325 horsepower, then it's too small and EVERYTHING has to change to hit 400.

GM TBI offers flexibility up to around 400 hp using fairly stock stuff.

Aftermarket TBI/TPI goes from there.

One of the biggest benefits of adding an ECM to the vehicle is knock sensing, don't overlook the advantage of integrated ignition & fuel systems. With knock sensors you get what you pay for and that's important when the noise of hedders and aggressive valvetrain are added to the mix.

Many factory ecms are looking for a vehicle speed sensor that your transmission lacks. You can add them to the cable or you can program that out. Just one more glitch that's solved with money :laughing:

If you look around there's a fair number of intakes offered with injector bosses and universal fuel rails that a guy can fit together at home, old style or vortec style. Throttle bodies can be very low profile, allowing a taller intake under our low hoods. You can get ridiculously tight with the air cleaner, much more than with carbs. Really, it's only a couple hundred cost difference to have a more sophisticated system that not only makes more power with it's larger intake, but has growth room.

Typical TBI fuel systems are 15-30 lbs. TPI systems run 45-85. Pressure helps efficiency but has added complexity and cost. So what you're willing to do to your fuel system is another decision variable. The trend is to higher pressures, so if you want to be able to benefit from future injector technology, higher pressure wins.

Both systems will want a later CS style alternator or the voltage drop at idle will funk things up. Plan for it up front, don't chase the ghosts later. Low voltage is also hard on ECMs.

good luck with your cool project!