Full Answer
Do vortec heads fit on TBI intake manifold?
However, the Vortec heads use a different intake bolt pattern that does not match up to the TBI intake manifold. There are ways around that by using a GM Performance Parts aluminum intake that bolts to the Vortec heads and features a stock mount for the TBI. The intake is PN 12496821 ($370 from Scoggin-Dickey).
What is the best TBI manifold to use?
Eldebrock makes a nice TBI manifold that should help the breathing a lot as the stock one is very restrictive plus the Eldebrock will take oversize TBI units too without a adaptor. More sharing options... This topic is now archived and is closed to further replies.
What is the difference between stock injectors and big block injectors?
The difference is the injector flow rates. The 5.0L injectors flow 40 to 45 lb/hr, the 5.7 ones are 50 to 55 lb/hr, and the big-block injectors flow around 75 lb/hr. We would suggest sticking with the stock 5.7L injectors to begin your testing.
How much power can a stock TBI handle?
around 275 hpStock small-block throttle bodies only flow around 500 cfm (compared with a stock Q-jet that flows 750 cfm). It's possible to make around 275 hp with a stock TBI unit, so rather than go nuts on a heavily modified TBI, I'd suggest you start by making sure the existing TBI unit and injectors are in good shape.
How much horsepower does a stock 350 TBI have?
210 hpWith all-new components and modern updates, this General Motors Gen 1 350 V8 puts out a reliable 210 hp and 300 lb. -ft. of torque at a work-friendly 2,800 rpm.
How much HP can a TBI make?
Stock TBI unit can make about 330 HP at its best with normal compression and cam design.
Which is better TBI or carb?
So most TBI systems can tolerate radical cams with durations up to about 250° with much more finesse than a carburetor. The engine will run smoother, idle better, start easier and provide better throttle response and cold driveability with TBI than a carburetor.
How much horsepower does a 5.7 350 have?
It's a 5.7L (350 cubic inch) small-block, V8 engine with a 4.00-inch bore and a 3.48-inch stroke. Depending on the year, make, and model of the car that it is equipped in, this engine is capable of outputting between 145 to 370 horsepower.
What is the difference between a 350 TBI and 350 Vortec?
The differences between them are that the TBI had the injectors right in front of the throttle plate, where the Vortec placed the injectors behind the throttle plate; and the TBI was a speed density system, whereas the Vortec used a mass airflow system to manage the fuel-injection system.
What is the fuel pump pressure for TBI?
The fuel pressure regulator is set for approximately 12 psi (30 psi on '94 & '95 BBC trucks). With a service range of 9 to 13 psi being considered good.
How do you convert TBI to Carb?
2:534:53Converting TBI to Carburetor, tips and tricks - YouTubeYouTubeStart of suggested clipEnd of suggested clipYou'll cut off those steel lines and and splice them into your fuel regulator. And then you canMoreYou'll cut off those steel lines and and splice them into your fuel regulator. And then you can control the pressure your your carburetor. Only needs somewhere between 3 to 6 psi anymore.
What's the difference between EFI and TBI?
ALL fuel injection can be classified as Electronic Fuel Injection (EFI). TBI is an EFI setup that utilizes Throttle Body Injection (looks like a carburetor). The TBI units have two injectors that meter the fuel for all the clyinders at once (again, similiar to a carburetor).
What is an advantage of a TBI system?
Improves performance and fuel economy TBI easily yields higher output in the form of more horsepower, without having the need of complete servicing of the engine.
Can you convert a TBI to a Vortec?
"Can I swap a Vortec motor in place of my TBI motor and does it just bolt in place?" Yes, you can swap a Vortec motor in place of a TBI motor, but no, it doesn't bolt in place.
Which is better TPI or TBI?
TBI is basically a high tech carb. The injectors are mounted in the throttle body. TPI is usually multiport fuel injection. There is one injector per cylinder, therefore more effective.
What is a TBI?
The GM TBI is a speed-density system, which assumes the engine ingests a given amount of air at wide-open throttle (WOT). Mass airflow systems measure the air entering the engine, but speed density systems like those used on these TBI engines do not.
How fast does a wide open throttle increase fuel pressure?
You should test any fuel pressure change with a WOT acceleration run in Second gear from about 30 to 60 mph.
Why add a longer camshaft?
Adding a longer-duration camshaft with more lift will drastically improve airflow and increase power at a higher engine speed. The problem is that it will require additional fuel that will mean changes to the base fuel map in the computer. We'll get to that in a moment.
Can a Vortec head make 300 HP?
These heads flow very well and would be a good choice to make 300 hp with a mild camshaft. However, the Vortec heads use a different intake bolt pattern that does not match up to the TBI intake manifold. There are ways around that by using a GM Performance Parts aluminum intake that bolts to the Vortec heads and features a stock mount for the TBI.
What is the bore of a 454 TBI?
The 454 TBI has larger butterflies and you may need to get your adapter plate bored out if doesn't have 2" diameter holes. The rest of sbc family are 1.68" bore. Since the 454 TBI was only put in vehicles with a manual or 4l80 if you are running a 700R4/4L60 you'll have to come up with a throttle lever that has provisions for a TV cable.#N#When I put a 454 into an S10 with a 700R4 I ground the levers off the 4.3 TB and the 454 TB and welded the 4.3 one onto the end of the 454 throttle shaft in place of the original. Everything worked fine.
What bore is a SBC 454?
The rest of sbc family are 1.68" bore. Since the 454 TBI was only put in vehicles with a manual or 4l80 if you are running a 700R4/4L60 you'll have to come up with a throttle lever that has provisions for a TV cable.
Can a 454 TBI run 350?
The big problem with the 454 TBI body is the idle air holes are too big for the 350 and they don't like to idle correctly and are hard to tune, the truck will run just fine with the 350 injectors and the basic stuff minus the boring of the TBi unit. You're just trying to improve the TBIs flow to the best that you can, it's not necessary to bore but you'll be leaving a little on the table. Which I think is always better than sacrificing driveability which is the whole point of fuel injection. The most flow gains you're going to get doing all the mods is 75-100 cfm improvement over 450-500 cfm. These mods won't change the world but they will definitely help since your vortec motor will be at the limit of efficient flow.#N#Everything is compatible 454 to 350 the bores are just bigger. And the idle air bypass holes are larger
Is a 4.3 TC good?
The stock 4.3 TC is usually pretty good behind a 5.7. The stall speed will be slightly higher because of the larger engines increased torque. It'll give better performance than using a 5.7 TC out of a full sized truck. Those are pretty tight.#N#My 89 loaded 4.3 ext cab had what I considered the best TC I've ever driven. It was almost what you would call a break away TC. Any time you gave it a little kick in the skinny pedal the rpms would jump 3-500 and it was a ball to drive. Under very light throttle it didn't slip much so the mileage wasn't hurt much. I traded it on a new 93 5 speed 4.3 which I thought was a dog after the 89. Traded in that truck in less than a year. Back then trucks cost 1/2 what they do now and I normally traded every other year. Last time I was at the local dealers I looked at the new Blazers. You got to be kidding me, $45-46 for a Blazer?
