Hello ALL thinking of rebuilding my 1989 blazer 4.3L V-6 4x4....But want to modify the engine for more power & torque ...my question is has anyone ever done so...If so can u please post the mods and ur satisfaction...re; cost ...labor.. over all performance. thanks in advance

 

If you are up to alittle modification work, it may be easier and cheaper to do a v8 conversion than to build up your 4.3L. Just a suggestion. I bring this up because there is a MUCH larger aftermarket for the 350 v8 than there ever will be for the 4.3L TBI LB4, not to mention the performance differences between the two engines. Even a mildly modded 350 will kick the snot out of a wild 4.3L.

 

Sure is true about the performance parts available for v8's. But I'll bet you're like me and would probably not place any more investment in the v8 than you would in the v6. In other words, you would purchase a mild improvement in a cam and valve springs and perhaps a decent exhaust with a good quality intake. This way wether you had a v8 or a v6 you would still be able to drive it on the street. So now what you end up with is a decision about what kind of investment you are willing to make in OTHER things.

Are you happy with the way the car handles and stops and such? If so then the difference that will show up with a v8 in cooling, handling and stopping may bother you and make you wish you had settled for the obviously simple thing. Even the front spring rate (new springs) should actually be changed to add the v8. Even looking to purchase a late model v8 could lead you strangly astay. Rebuilding one stock could cause you to end up with even less horses than your 4.3 has now. Some Camaro 305 motors are certainly in that catagory.

Although parts are not as readily avaible, it just so happens that at least one major manufacturer of aftermarket performance parts is helping us out. Edelbrock is making a cam, lifters and should also have valve springs and such to finish the job. Whats even better is that they are also building this to match an intake manifold for either TBI or 4 barrel carb. Your choice. I actually feel like the best choice may well be the 4 barrel carb manifold with the TBI adapted to it. If you're like me and looking to buy used parts, this may be an answer. Along with this, if you look carefully at the performance chips available to go with performance changes you can find chip to match the mods. One more thing, the tranny could use a shift kit. Regular engine parts such as crank and pistons are readily available in both original and high performance for both. I have also seen modern hotter distributors available from, I believe, Proform. Could be wrong. Saw one someplace. Have to retrack and take some notes.

I didnt write down all the prices as I went along and looked things over. The headers I saw are about 150 plus the mufflers and such. Be aware that MANY headers are available and most cost plenty. I happen to be in the process of stripping an engine down for the same thing, but have not done a v6 before. I have been warned that 3 cylinders on a side do not sound as good as 4. So be sure to add a crossover pipe. Of course you ough to do that in the v8 also.

I do own a vortec s15 jimmy 4.3, 95 and it'll eat many stock v8's. I have never looked inside that one. It is theoretically a higher performance model and I should have nothing but trouble with the injection according to some.

Now for the differences from the v8 perspective. When you look at the price of everything made for the sbc v8 chevy motor, please be aware that MOST of the cams and other engine parts will be listed for the plain old fashioned pre 86 model. This v8 is not nearly as well built originally as the modern v6 or modern v8's are. So if you went to a v8 you should go to a late model v8 with a roller cam and built to tighter specs from the factory even though you may well be taking either one apart. The later, closer tolerance engines will still be better after a normal rebuild than if you were starting with a pre 86 or older motor. Only very well built, hand crafted motors from those days are up to the same standard. Machinists and mechanics that worked to tolerances that close and that well are getting harder and harder to find.

I do feel that those of us interested in staying with the rest of the world in the performance venues should pay very close attention to building our 4 and 6 cylinder engines to produce more power rather than invest in the ever gas guzzling v8's of old. BTW I have 2 great running Chevy small block v8's right here and would NOT sell either. But

 

Holy freakin' novel batman... Although your statement on "gasoline and cubic inches goes hand in hand" is most of the time true, horsepower can be had in a v8 with reasonable fuel mileage. Friend of mine just built a '70 350 block, bored/stroked to 402cid and put it into his '74 Camaro. He bought the Edlebrock performance package consisting of cam, heads, intake and carb. At 420hp & 465ftlbs on the dyno and backed by a tremec 5spd manual tranny, he gets 19mpg highway and at the tail end of last season he was running 12.3s in the quarter. That is pretty damn respectable for a plain old fashioned v8. His cam is a roller with roller rockers. Lets face it, even the gen 1 small block can be built (and not necessarily hand built) to perform just as good as any modern engine in terms of reliability and efficiency. Efficiency all depends on how well matched the components used are (intake runner sizes/lengths, etc) and how the engine is tuned. Even todays EFI engines with proper tuning can get **** poor gas mileage.

I also have a friend with a '94 Tahoe with the 350 tbi. He gets 22mpg highway and 18mpg around town. Much larger vehicle than an s-10 blazer with 2 extra cylinders and probably gets better gas mileage than most stock s-10 blazers do.

I think, dollar for dollar, I could build a 350, with all associated suspension changes factored in, that would spank a 4.3L. Heck, with a 4x4, I think all that is necessary is to crank up on the torsion bars.

But, this is all besides the point of this thread.

 

Just trying to help out with the question as posted. If I can be of any more help please advise and I know where to find prices. Just as easy for you to get on summit racing site and go through the whole setup with a wish list or something. Watch out for the cam in the v6 it uses stock lifters and you would have to buy a new set, I believe, with the cam change. There may well be a fairly large cost right here. They are NOT included in the already large price for the cam. Dont forget to go to double roller timing chain in the process. My problem is finding shiny brackets and pulleys for the motor. Not performance parts. Having a Chevy P.A.W. catalog for a reference tool makes life easier too. Good 5 dollar investment. Fuel pump in these cars and most Chevies is not quality and could use some help.


Do remember one thing, there are millions of cars out there with 4 bangers in them right now that will literally blow away many a chevy anything. I owned a carburated Mitsubishi (sp?) in and model year 79 that topped calmly at 135 miles per hour on the hiway all day long and got the best of many american v8's also in short distances. 2600 fire arrow (this was 4 cylinders, not 6) with tiny two barrel carb and real points. Cute little hemi head. They go a lot faster these days. Used it to tow a camper trailer back and forth to work between Pennsylvania and Virginia every weekend for a whole summer. This thing looked like one of the many little fastbacks of those days. Toyota had millions of them too. Datsuns 240, 280 couldnt get close to it. German air cooled things would give up. Look at all those brands and their performance now. Trailer slept six and not tent camper.

When I needed it to and used the 5 speed and torque of the motor correctly, I could get 50 miles to the gallon. Without trailer, no racing and not over 55. But it could be done. Carb, points.

Ran across a site of interest for gas mileage figures.

http://forums.pickuptruck.com/showfl...b=5&o=&fpart=1

It is now my opinion that the only true American car manufacturer left is Chevy and I am a most loyal customer, wont buy anything else anymore. But the Chevy v8 (from chevy) has also ALWAYS been the least economical automobile engine for its size, power and torque. Its intake, exhaust and smog control systems have always been the PITS. I also get good fuel mileage from a 383 with single quad and sorta mild cam in a Camaro. A properly tuned engine will do that. Heck our 327 pickup gets around 18 all the time. None of this is factory stock though.

 

Here's something to keep you salivating:
Bored & Blown Vortec 4.3L