What is the weakness of the 4.3L V6?

[CrazyGM]

I am planning on building up my V6 from a 1990 C1500. I need to know the weakness of these motors. Thanks

[Stevonator]

They're made by GM...LOL If I had a full-size I wouldn't even be looking at building up the V6...you're far better off and have far more options with a V8.

[Supercharged-ZQ8]

The main weakness of the 4.3 is the fuel delivery system. If you can upgrade the injectors, you will be able to produce as much power as a V8. But, there are only a couple options available for manifold and injector upgrades. Afforadable Fuel Injection has a manifold available (road testing is still underway, but it looks promising). It all depends on what kind of power you're wanting to get out of it -- after you decide how much you want out of it, then you can decide on what mods to do. There are more than a few 4.3s that have produced close to (if not over) 300 rwhp (a figure WELL into the V8 range).

But, being that it is a 1990 V6, you may not have the same fueling liabilities as the '96 and newer motors. I am not as familiar with the pre-'96 motors as I am with the newer ones. Options ARE available -- it's only limited by your vision and your wallet.

[Matt 4.3 TBI]

TBI is FAR easier to get more fuel into than the later engines. You can upgrade the injectors (45pph stock) in 5pph increments up to 80pph (!!). That much fuel is difficult to tame for idling, tho. A custom-designed chip, or an adjustable DFI system is a must when upgrading injectors to get the most power and best economy out of it. You can tune injectors a bit with an adjustable fuel pressure regulator, but it is by no means a precision fix.

I've been talking with my buddy who did the custom chips for my Blazer, and he recommends I upgrade to at least 55pph injectors before I start thinking about boost, just to be safe.

I should add that pre-96 4.3's biggest weakness is the heads. You should give though to putting on a set of 96+ heads. You can then use Edelbrock's Vortec to 4bbl manifold with a TBI adapter plate to get the fuel system on it. A lot can be done with the stock heads (mine flow 200cfm now!) but stock Vortecs still flow better. Even if I used larger valves, a set of equally-finished Vortecs will outflow mine any day of the week.

[CrazyGM]

I have a set of vortec heads (not sure of the exact year) and a q-jet intake for it. But MPFI is a bonus, TBI is what I currently have.

[Hammer]

mpfi is so much better for economy, reliability, tuneablity and driveability than carb setups (usually) and imo better than tbi/sfi/or even tpi. tpi is my second favorite.

-hammer

[Maximus]

What hammer said holds true about anyway you look at it.BUT a carb can make large horsepower and can be tuned too.Enter in TBI to the mix.It has the same characteristics and function as a carb to a point.You CAN make large horsepower with a TBI no matter what you have heard.You have about the same options with a TBI as you would a carb.You can pick intake designs like you would a carb cams and so on.But you will have the reliability and consistent AFR as fuel injection.No you won't make as much power and efficiency as fuel injection but you won't have the flaws and draw backs of a carb.The TBI is also flexible for improvement.You can add bigger injectors,adjustable fuel pressure regulators,better flowing throttle body,all the usual engine upgrades too.You can also supercharge them"CPI can't" and run nitrous on them.There is also carb style options like shaker hoods for a ram air effect or cowl induction.TBI in a true since of the word is a middle ground between the good and the bad lol.I in all honesty would rather have TBI in my daily driver than CPI or SFI.I actually picked my truck over a CPI version.I mean let's face it TBI is almost bullet proof.You rarely see any problems with them and if you do the costs are little compared to the other systems.With all 3 fuel injection systems they all have good and bad attributes.If I personally could build my own 4.3 fuel induction I would use a CPI intake with a SFI throttle body with upgradeable injectors like the TBI since it's the only one that can.But I would keep it a speed density system for low cost and reliability.I have a CPI intake that I really want to play around with and see just what I could do with it.OK I have rambled on long enough lol.

[CrazyGM]

the heads that I have are from a 94-95 4.3L

[CrazyGM]

teh eXtra set of heads that I have are from a 94-95 4.3L

[ZR1 S10]

I am planning on building up my V6 from a 1990 C1500. I need to know the weakness of these motors. Thanks

Definately not 5800rpms :rolleyes: :cool: :D