4.3TBI to 5.7 Vortec

[KaidenP2]

Hi guys, I know this has been discussed a few times but here’s my scenario and findings:

I have a tbi 4.3 in my truck (truck is a 95 c1500) . I had the opportunity to buy a vortec 350 which came with the computer and transmission. Anyway I’m aware I need to swap all of the wiring to do the swap stock vortec. I also have a tbi 350 out of a 95.

My question’s are:

How do I go about this? I don’t mind buying a vortec to tbi conversion manifold and switching all of the sensors from the tbi 350 onto the vortec and putting the prom in and using the 98 transmission as well. (I understand I will need a chip burn eventually for the roller cam to run properly)


Would the tbi 350 with vortec heads and an aftermarket vortec manifold work better?

Thanks in advance,
Kaiden

 

[PlayingWithTBI]

A few things - the TBI has a "peanut" flat tappet cam so the Vortec's roller cam is better. The Vortec has a crank sensor and a different distributor than the TBI. If you want to put the Vortec heads on the TBI block you'll get some gains in flow but, you'll still have the peanut cam, and you'll need to keep the TBI computer controlled distributor. You can convert your TBI block to accept a roller cam which will give your better performance but, how about exhaust upgrades? How far, how much do you want to go/spend? A conundrum for sure.

 

[KaidenP2]

Thank you for the reply!

So to clarify if I were to convert my tbi to vortec heads I would just need a vortec manifold and all will bolt up fine and plug and play?

How would I go about the cam conversion? Do I need to buy a kit or should everything from the vortec work?

for exhaust I was just planning on fabricating my 4.3 y pipe and going stock exhaust for now

I’d like to keep it fairly cheap but a little spending is no issue

 

[stutaeng]

Is the Vortec a complete pull out with wiring harness? Or just stand alone matching computer?

I'm not familiar with TBIs, but would think you could just add the Vortec sensor wiring to your existing wiring harness? Haynes manual has the wiring diagrams for both TBI and Vortec in the same book.

 

[PlayingWithTBI]

So to clarify if I were to convert my tbi to vortec heads I would just need a vortec manifold and all will bolt up fine and plug and play?

Chevy Performance makes a Vortec/TBI intake but it's mucho $$$.
https://www.summitracing.com/parts/nal-12496821

Best thing to do is to go with an Edelbrock Performer Vortec dual plane intake and a TBI adapter plate. You may have to get a tune in the end depending on how hot you wanna go. YMMV
https://www.summitracing.com/parts/edl-7116
https://www.summitracing.com/parts/prf-60118

How would I go about the cam conversion? Do I need to buy a kit or should everything from the vortec work?

There's a couple ways to go, you probably have the bosses in the valley for the spider and dog bones but, you may have to drill and tap them for it.
https://www.summitracing.com/parts/sum-150123

Or, this way, with link bars (and I'm not recommending this setup over any other)
https://www.summitracing.com/parts/hrs-cl110235-12

 

[Erik the Awful]

For plug & play, drop in the TBI motor and computer.
If the TBI doesn't have a distributor, you'll need to find an 8-cylinder TBI distributor.

If you decide to go Vortec: (I did the Vortec into a TBI swap, but with a much larger cam than factory. I initially tried using the TBI, but switched to an aftermarket system.)
I used a Summit Vortec intake and a TBI adapter plate.
I had to rework the TV cable bracket.
There's no EGR provision on aftermarket Vortec intakes.
I had to rework the brake booster vacuum routing. Basically, I bent the factory tube that runs up the driver's side of the intake and ran it between the distributor and throttle body.
With the Vortec motor, you can keep the plastic timing cover and just leave the crank sensor unhooked. Since I did an engine-out rebuild, I went ahead and swapped to a TBI timing cover.
You still need the 8-cylinder TBI distributor.

 

[Grant Henderson]

So what exactly is the consensus here?

I have a 1995 c1500 manual with a 4.3, im looking to drop a 350 in it.

I would like to do it as cheap and clean as possible. My biggest concern is getting everything working correctly with the factory set up, I have a 1995 k1500 auto donor truck. I guess what im asking is it just as simple as getting a 1995 c1500 manual 5.7 computer and dropping everything in (other than motor mounts etc).

 

[PlayingWithTBI]

I guess what im asking is it just as simple as getting a 1995 c1500 manual 5.7 computer

You could or just get a PROM for your PCM.