3.8 V6 swap to 4.3 V6 ??

[rangertom]

Ok right off the bat i know all of the purists are gonna kick my butt for asking about this but... I have an 84 Cutlass with the buick 3.8 V6 in it, and i have been tossing around the idea of swapping the engine with a 4.3 V6 like what is in my 92 chevy silverado. I like the 4.3 and am proficient working on it and know the gas mileage is decent, in my head i'm figuring i might get even better milage than my truck without the drag a truck has and i would really like to have the fuel injected and throttle body instead of the carb. I know the next question of everybodys is why not swap a V8 and my only answer is fuel mileage and i have no intentions of racing my car ever. i just love the ride and cruising in it. So my question is what does everybody think, and yes i really want to hear honest opinions, i'm not exactly a GREAT mechanic but with the4.3 V6 in my truck i have NEVER had to take it to a mechanic... and i knew NOTHING about cars when i bought that and that is how i learned to diagnose and fix my own vehicle. let the opinions begin...lol

 

[rangertom]

Nobody, i'd really like to hear some opinions and or anybody done this swap ? I know i saw on the forum at on point somebody said they had a vortec 4.3 V6 in their Gbody but never said more about it... any help would be greatly appreciated.

 

[DRIVEN]

My opinion? You won't be gaining a ton over the Buick if it's in a good state of tune. I'm admittedly not a huge 4.3 fan but these are the facts: If you go to the 4.3 and just use a TH350 behind it you'll be leaving both performance and economy on the table. If you put a 700-R4 or 200-4R behind it you'll need to re-gear the rearend to take full advantage.
I think you would actually get equal to or even better mpg using a TBI 305 with an overdrive behind it. My 305 is carbureted and still gets 20 with good quality fuel. The TBI is probably good for another 1-2 mpg. Maybe an aftermarket system, such as Holley's ProJection (which is basically a stand-alone GM TBI) on an Olds 307 would do the same thing. The Olds 260 was no powerhouse but was known to do as well or even better than the V-6 options of it's time.
A small, efficient, torque-oriented V-8 will get you the best mpg. The small V-6s just have to work too hard. I think it makes more sense to either live with the 3.8 or just do a V-8 swap. It'll probably cost you no more to install a SBO or SBC than to go with the 4.3 if you do the math.

 

[jae]

I'd have to agree with Driven on this. While you'd gain torque with the 4.3 over the 3.8, hp would still be low. I mean, the 4.3 really a V6 version of the Gen 1 SBC so some parts are readily available cheap & so many V6 parts are available too but performance-wise they are expensive to build-up for performance.

Not discouraging you, it's an interesting project, would be different, but the gains really don't justify the swap, IMO

Whatever you decide, good luck.

 

[wagonrod82]

I would go for it. I pulled a 3.8l chevy v-6 from my 82 malibu wagon. I had a 4.3 sitting in the car running but things happened and I pulled it out again. I decided to run a sbc but still wanted the fuel injection. I currently run the tbi and also swithed out the turbo 350 for a 700 r4. When i get it dialed in just right i will post some numbers. I don't plan on it tearing up the drag strip to bad but will be looking for 22 mpgs.

 

[DRIVEN]

Wagonrod82's project would make perfect sense. Replacing a Chevy V-6 with a Chevy V-6 is practically a bolt-in. But when you're doing a BOP -> Chevy, or the opposite way, there's much more involved. Enough parts would need to be replaced to make me think twice. A TBI 4.3 in a Gbody isn't necessarily a bad idea. The engineers thought it was good enough for the Monte Carlos in the mid-80s 😀 .

 

[rangertom]

I appreciate the opinions fellas, Performance is definetly not what i have in mind just a little better fuel mileage and ease of repairs, like i said my 92 chevy truck had that engine and it went 360,000 miles before i somehow cracked the block and heads and it went that far with NEVER going to a shop or mechanic, i did all the work with no knowledge and only a chiltons in hand. so i guess t me it means swapping in an engine that i know and mostly understand that i know won't need a ton of maintenence or constant tuning and i can simply enjoy driving my cutty instead of wrenching all the time. as far as having a TBI instead of a carb i already know i can tear apart a TBI with no formal knowledge and clean it and reinstall and run it, the carbs kinda got me scared to mess with it and right now my carb and engine are definetly not tuned to perfection.

 

[DRIVEN]

Sounds like you've already made up your mind. But if you can keep a TBI 4.3 on the road you can certainly keep a TBI 305 on the road. I truly feel you're selling your car short by using a 4.3. If it cost the same, takes the same amount of work, get's better MPG, and has more power, why wouldn't you choose the V-8?

 

[rangertom]

You make some excellent points Driven, tell me this because i really have no clue... can i put a TBI on my current engine ? i thought i've read here of other guys doing that and also going from a TBI to a carb by just changing the manifold? is this possible, what would it take to do that? I suppose part of my issue is the tuning but also like right now when it's cold and i drive my car somewhere and shut it off and go in for a lil bit, when i start it back up i have to give it alot of gas to rev itup when it starts otherwise it stalls and then i have trouble starting it back up unless i hold the gas peddle down and then it just revs and smells of all the gas being wasted 🙁 i'm assuming that is my carb acting up... otherwise the engine runs great and i'm not dissappointed in it except the carb issues.

 

[DRIVEN]

You could get creative and build a hybrid distributor. I couldn't tell you exactly how though. The rest could be adapted pretty easily. You could probably use the Holley system or something similar.