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Discussion Starter · #1 ·
I'm just wondering what a complete 4.3 Vortec with harness, manifolds, computer and so on would be worth? Is there a desired year for this motor? I've heard that there was an issue with imbalance in older blocks, was this the Vortec version or just in non Vortec labled motors? I'm looking for average used price but if you know new prices I'd like to know that too.
Thanks:D
 

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i have a 95 vortec 4.3L and have no trouble with it, but my dad has one (non vortec) in his 88. he had to rebuild it 3 times since he bought the truck new. twice in the 2 years after his 3 yr warrenty ran out.

just my .02

:cool:
 

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I'm not familiar with the engine production dates, but most pre LB4 V6 engines were not manufactured with a balance shaft, resulting in problems with those motors. All the newer engines, the LB4's,L35's and newer, are Vortec engines. These engines are definitely the better ones to go with. If I recall, the going price on a newer V6 Vortec w/ computer is around $5,000.00 to $6,000.00 dollars. I don't know if this is a good price or not. My feeling is that it isn't. Hopefully this will help.
 

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"Vortec" is a bad identifier since the word appeared on every flavor of 4.3L V6 ever found in the downsize Blazer/Jimmy.

There are at least 4 different ones:

TBI non balance shaft (86-95)
TBI balance shaft (93-95)
CPI balance shaft (92-95)
SFI balance shaft (96-current)

To make matters worse, there's two versions of the TBI/CPI balance shaft engines; one with (plastic timing cover) and one without (metal timing cover) a crank position sensor. (Make sure you get a matched ECM and harness with your engine!)
 

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Discussion Starter · #7 ·
u2slow said:
"Vortec" is a bad identifier since the word appeared on every flavor of 4.3L V6 ever found in the downsize Blazer/Jimmy.

There are at least 4 different ones:

TBI non balance shaft (86-95)
TBI balance shaft (93-95)
CPI balance shaft (92-95)
SFI balance shaft (96-current)

To make matters worse, there's two versions of the TBI/CPI balance shaft engines; one with (plastic timing cover) and one without (metal timing cover) a crank position sensor. (Make sure you get a matched ECM and harness with your engine!)
Ok dumb question time... :confused:
I get TBI and I get SFI but what the heck is CPI? Some sort of port injection I would guess? Also the overlap from internally balanced and non internally balanced blocks from `93 to `95... is there an easy way to spot the difference? Would you happen to know any of the codes that might be stamped of the block that would help with this id'ing? What I would be after would be an internally balanced TBI version, with metal timing chain cover ;) thanks for that tip! If you happen to know of any good info on the web I could read that would be great.
 

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Discussion Starter · #8 ·
Ok I went diggin' on the net and answer most of my own dumb questions. should have remembered the harmonic balancer on the front of the crank, I knew that one... really I did. And I was sort of able to get an idea of CPI as well, it sounds like the prefered induction system actually.
Would still like any links you might have on the Vortec 4.3's or any stamped code to be found on the block that will help me find a good one when the time comes.
Thanks
 

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I've been trying to find a manual I purchased on the 4.3's, where to find the block stamp, it's definition, etc. I will leave the info here when I find the ruddy thing. In any case, and for whatever this is worth, if you happen to pull a 4.3 out of an existing carcass, I guess the VIN engine and model year codes would somewhat help.

The 8th code on your VIN is the engine code
W... 4.3L Central Port Injection (CPI)
X... 4.3L Sequential Fuel Injection (SEFI)
Z... 4.3L Throttle Body Injection (TBI)
4.. 2.2L 4 banger w/ Multi Port Injection (MPI)

I recall this manual as stating that the weaker of the 3 V6 Vortecs was the X engine, and more of the S-series wound up with TBI and CPI setups. A popular conversion is throwing the CPI setup, in replace of the TBI. It's a direct bolt up, and apparently came with some addtional power advantages over a true CPI setup (for the life of me I can't see where).

Actually, if I recall, you will find the stamp on the lower left side of a V6, around the oilpan. I think there are two, but I cannot remember exactly.

FYI, engines with a non balance shaft did not exist in the 1994 production year... and the only engine that I am aware of that came with the plastic timing covers were the 4 cylinders, not the V6's... If I am incorrect, please let me know where you found this info that states otherwise, I am curious to know.
 

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Non-balance shaft 4.3's have a timing cover just like a chevy small-block (rounded on top).

The balance shaft ones (with metal covers) have a raised squared-off area above the camshaft where the balance shaft sits.

CPI stands for Central Port Injection. This is a batch-fire injection system. The manifolds are bad for carbon build-up. SFI is the better way to go.

http://www.marine-engines-inc.com/gm03.htm

Also notice the funky aluminum oil pan.

Vin "X" is the "detuned" 4.3L S(E)FI from 96-onward. All are balance shaft.

Vin "W" is CPI or SFI depending on the year; CPI for 95-older, SFI for 96-up. All are balance shaft.

Vin "Z" is the troublemaker. It can be balance shaft or not depending on the exact year and vehicle. Last year for it is '95.
 

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Discussion Starter · #12 ·
For anyone intrested I've found a marine suppier that has the marine 4.3 vortec complete less w/pump, flywheel, and fuel system for around $2500us. Should push a Toy around quiet nicely, now I'll just need to pay for it.. :rolleyes:

 

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I traded a 4.3 vortec from a 94 blazer with lots of stuff to j.b/mike p for two 350's + 200 and all the crap I need for my conversion minus t-case / tranny and adapters. Yes they are carb. No, I'm not crazy, I HATE WIRES!!! :angry
 

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I think I got a good deal on mine. It is out of a 92' Astro with 250,000km on a "All you can carry" special at PYP in Kelowna. Paid $35 after taxes and went back the next day for computer/harness/TBI/and all other censors for $50. Now to rebuild it.

How does this sound for a rebuild,
.030 flatops and the 64cc chamber heads. Orignal comp is 9.2:1 Should hit 10.5-11.0:1 shouldnt it? Looking at the heads this should not be a problem as the design of them are so much better than a SB that they will flow anything dumped into them. Great big valves and, straight ports intake and exhast! The roller cam will feed them just fine (Lots of lift and duration by the look of it) and a replaced TB off a 5.0 with larger injectors will increase fuel. If needed Edelbrock and I am sure others make a chip that plugs right in. With a clean flowing exhast I can see the possability of 250+hp.
What do you guys think?
 
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