TBI Vortec?

[81Cheyenne]

I'm going to build a new motor for my 81 C10. I have a brand new set of Vortec heads sitting on the shelf and a complete TBI setup (on a non Vortec intake so I'll have to buy one).  I have an extra 350 block and have thought about maybe even bumping it up to a 383. I'm pretty much a neophyte when it comes to fuel injection so this would be a new experience for me but I like the idea of the added response and hopefully fuel economy. I'm looking for some advice here, is TBI worth the expense and work of fitting it up or would I be better off just going with a carbeurated intake?

[Captkaos]

Are you building for speed or dependability?  Do you have a harness or are you going to have to get one?

[81Cheyenne]

Mostly dependability. Yes, I have a complete (engine compartment) harness.

[Captkaos]

If you have most everything, I would do it..

[Blue 82]

GM designed TBI to feed a 200hp 350
The higher you go, whether it be in cubic inches or desired HP the more tweaking it's gonna need. (also fuel/air and $$$)
 
Getting 350 dependable HP out of a Vortec headed 383 with a carb is easy, a 16 year old kid with a Hot Rod or Car Craft subscription could do it.

Getting 350hp out of a 383 TBI is another story. Unless you have deep pockets, a lot of spare time and patience and are into burning your own chips, you may want to think otherwise. (remember the 200hp baseline)

The Vortec heads will require some plumbing to make the EGR functional, as the vortec heads do not have the exhaust crossover.


running 200hp injectors ain't gonna work
Some have tried the Cop Car injectors (9c1)
Some have tried the bigger 454TBI injectors with the 2" bore Throttle body (vs 1 11/16" for the 5.7)

You are gonna need to see what the TBI is doing should you decide to proceed with you TBI makeover. Guessing won't cut it....







here's some free software
http://winaldl.joby.se/

[81Cheyenne]

Wow. Looks like a pretty steep learning curve. How much difference is there in fuel economy between TBI and carb? Maybe I would be better off going old school. Would it make any difference if I stayed with 350cid?

[Blue 82]

Wow. Looks like a pretty steep learning curve. How much difference is there in fuel economy between TBI and carb? Maybe I would be better off going old school. Would it make any difference if I stayed with 350cid?

For drivability TBI wins (cold/hot starts etc...)
For MPG TBI has a slight edge (on a stockish setup)
For low end torque under 2000 rpm TBI wins
For HP above 4500 Carb wins
For anything over 300hp (for the average Joe) Carb wins (there are some that would disagree but they have an intimate working knowledge of TBI, but raise the bar to 350 or 400hp and the story changes)

For reliability I think TBI has the edge
GM built Millions of TBI trucks (and carbs too)
I've owned many of each
TBI is easy to diagnose (with a paper clip) and work on

It's a matter of preference
I like em both

If you were gonna build a (mildly warmed over) TBI motor stick with the 5.7
your chip burner (and your wallet) will thank you for it.
TBI takes a bit more time and effort to tune
just don't go wild ( you are not gonna run 12's with a TBI truck)

[Blue 82]

here's some TBI info

http://www.aldlcable.com/

[81Cheyenne]

Is it necessary to run EGR? My state doesn't have emissions testing and I would like to avoid having to plumb for it. I'd like to keep my headers too.

[TexasRed]

If you're going to get a chip burned for it, then you can have the EGR taken off the code. Same thing if you megasquirt it, since you're creating your own code.

[Captkaos]

I agree, if you are going to go to 383, you are going to have to do some work on the ECM side and some other changes.
If you are going for a mild update on engine though and are going for dependability, TBI is the way to go for cheap.

If you have a 350, you can search around on the net for L05 builds for the caprice 9C1 motors, their came is different than the truck version, but you can get fairly respectible power out of one... and still use TBI,.

[Blue 82]

at this point you have 3 options

a) a fire breathing 383 with a carb
b) save a few bucks/ a fire breathing 355 with a carb
c) an approx 250hp torquey TBI 350/355 that gets decent economy with gas at $4 a gallon with no end in sight

[81Cheyenne]

Here's how I'm going to use the truck: First of all, I like to hunt and fish so I would like to be able to pull a fishing boat (with a slide in camper on on rare occasions). I will want to have a little fun with it but it won't be a street rod. I'm thinking on eventually ending up with a 700r4 with a 3.73 posi but it'll probably have a th350 with a 3.08 to start with until I can afford it. It won't be my primary vehicle.

I have a Holley spread bore Qjet replacement and also the TBI. I don't have a Vortec intake for either. The TBI came off of a 90 GMC 2500 (I think).

[TexasRed]

I have a Holley spread bore Qjet replacement and also the TBI. I don't have a Vortec intake for either. The TBI came off of a 90 GMC 2500 (I think).

I couldn't get my 4175 to stop leaking . But if you want to do spreadbore, the 4175 isn't bad (unless you got the double pumper 4165) but you might be better with a quadrajet. To get decent economy out of the 4175 you kind of have to run a dual stage power valve.

[81Cheyenne]

How well do those adapter plates that convert a 4bbl intake to TBI work? If I used an Edelbrock 2116 and put a plate on it, would it be as good as the GM TBI Vortedc intake? Might give me more options.