Thanks for the input. Going to try to get my hp up around 275 or so.

 

Here's a few articles:
4.3L Vortec + 1 Cam = 42 Extra Horsepower
&
Hotrod.com - The 3/4 350

But both are carb'd and no computer controls. With the modifications in the 2nd one, you would need some pretty decent tuning to get it to run that good with the factory injection & ignition controls. The cam should be a straight forward install and shouldn't require much tweaking if any.

 

Ok, maybe I am a little confused here..... so my engine, the one pictured here, is a vortec as well, just a different method of injection. Also, the main difference between my wifes Vortec in her 94 Blazer, and Mine from my 91, is the method of fuel injection TBI-vs-CPI and a cam?

Or is there more to it? So basically, a cheap upgrade for me performance wise, would be to snag a cam from a vortec and put it into my 4.3L?

[IMG]local://upfiles/2134/D0BF7F532DBD4587BDB96E53ED73893C.jpg[/IMG]

 

Cams are cheap yes, but the installation is the killer with them. I am seriously considering picking up a new cam/lifter set and installing it in my Bravada while I have the intake off replacing the intake manifold gaskets. Only thing I need to look into is if the timing chain cover can come off without pulling off the oil pan (which requires pulling the motor on the SCFI motors with aluminum oil pans).

But yeah, the injection and mostlikely the cam is the difference between your '91 4.3L and the '94 4.3L. Instead of picking up a stock cam from a CPI motor, look into Comp Cams for an aftermarket cam kit. It will give you much better performance for your $$$.

 

I'll have to look into that. What should I look for when looking at a cam replacement?

 

I think your still misuderstanding what Vortec is. Vortec is the design of the heads. It is the way the air flows through them. As the years progressed, GM improved the air flow. This allows more air into and out of the combustion chamber. More air means you can add more fuel. More air and more fuel mixed together means you can get a bigger bang, more bang is more power.

Cam will control the power curve of an engine. You can get a cam that will be extremely powerfull off idle (towing), or one that will make the most power at higher rpms (racing), or get one that goes somewhere in between them (stock).

To confuse or clarify things just a tad bit more. GM has two versions of the 4.3L engines, one is the Vin W engine, and the other is the VIN Z engine. One is considered the high output engine and the other isn't. The HO (high output engine) creates more power. By more power that means more top end power, and less grunt off the line. You could think of a HO engine as a stock performance (racing) engine, and think of the regular engine as a towing engine, or work horse engine.


You have to think of an engine as a system. It is made up of numerous subsystems. Subsystems include cooling, fuel, timing, combustion, ignition, lubrication, air intake, air exhuast, etc... Each could be tweaked to run optimally, however they might not work as a unit well. Engineers have spent countless hours coming up with an engine that will perform well. This includes the aftermarket. You mentioned a new cam. Shop around, you can find a cam, or you can find a cam/pushrods/lifters as a kit designed to work as a team, and you can find a cam, pushrods, lifters, and intake as one kit. All designed to provide the best performance.

 

Ok, since I seem to have the workhorse engine, not the high output, could I just swap the heads from a high output and gain more right there?

 

Might be easier to swap engines. You would not just be able to swap heads. You need to know what type of cam you currently have roller lifters or flat tappet, if you use roller rockers versus normal stamped steel, then you would have to know the length or the push rods and valve springs.

So just swapping heads won't do it....but with money all things are at least to be tried....

 

You could swap engines, however you will also need to swap the ecm and wiring harnesses as well.

One thing to consider is the amount of hp/torque difference between the vin W and vin z engines of the same model year. Not really worth the effort to swap engines. I think you could make up the difference with simple upgrades. Exhaust, cold air intake, chip. Cam would be the next level.

 

i say to get you back in the game assuming its an automatic-


Nitrous- 100wet shot with a good tune
full exhaust
march power pullies
1.6RR's
modded stock intake box
K&N drop in filter
3000stall torque converter w/ shift kit, vette servos, tranny cooler
3.73's and nitto 555r's spraying out of the hole
then a 270ah cam, new valve springs and port/polish. its good for mid-high 12's. which is faster than your vette