3.8 V6 swap to 4.3 V6 ??

[onyxxtreme]

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

I was thinking about the same swap myself. Originally I wanted to do a 4.8 or 5.3 swap, but it would be so much cheaper to do a 4.3. But I want the late 90's/early 00's vortec 4.3. They make plenty of power and torque, and decent MPG's. Even if left stock, they have more power than any engine offered, stock, on a Gbody Cutlass.
I, too, have no intentions of racing my Gbody, and I only plan on cruising in it. The 4.3/4L60 is readily available, everywhere, and dirt cheap, so it would make a great swap. Go for it dude

 

[clean8485]

I'm planning something along the same lines. I have one of the 1981 Malibus that GM of Canada originally built for sale to Iraq. These cars were equipped with the 3.8lt (229 cubic inch) Chev V6, and a 3 speed floor shifted Saginaw transmission. Since the 3.8 and the 4.3 are in the same engine family, I'm planning on swapping a 4.3 into the car, and swapping out the 3 speed, for a 5 speed from an '80s Chev S10 truck. I've gathered up a correct 4 barrel intake from a mid '80s 4.3, so I can keep all of the emission equipment intact and functioning (mandatory here in Ontario), along with a 4.3 HEI distributor, and a set of tubular exhaust manifolds. I purchased a late '80s 4.3 engine with a roller cam and lifters, so I'm looking for a late '80s Chev flywheel for a one piece rear main seal engine. I'm thinking about a cam swap, and maybe some minor head porting, to see if I can get the 4.3 to produce around 200-225HP. The way I see it, the mid '80s Monte SS HO 305 was rated at 180HP, and they move along pretty well, so if I can get the 4.3 up to 200HP, then I should have a car that's fun to drive, and not get stung too bad at the gas pump. That's the plan anyway.

 

[King_V]

Here's a thought - though it'll bump against familiarity/unfamiliarity....

Something I'd always thought I'd like to do is adapt the SEFI system from the 1986-1988 front-drive 3.8 V6s (Vin code 3, BEFORE they became the 3800) only a rear-drive 3.8 equipped G-body.

Don't know how practical that is, and I'm sure the roller-cam specs from the 3-code 3.8 SEFI motor are more aggressive than for the carbed rear-drive 3.8.... aw, hell, I always liked how the 1986 Delta 88 I had felt in terms of overall driveability and semi-decent performance (good for the era). On the highway that thing would do 29-30 MPG, and accelerated fairly respectably despite a very tame axle ratio.

I still have a mass airflow sensor and I think the ECU from that car....


EDIT: of course, cost, and know-how/ability with one motor vs the other, and what you already have on hand, of course, can play a HUGE factor in all this . . those were just my meandering thoughts I've posted...

 

[oldmansmonte]

Not trying to be rude here, but I cringe every time someone mentions doing a 4.3 swap. I've owned 2 4.3 Montes and I've had a few friends and family with the later 4.3's in blazers and vans and what not. I'll say this, the later ones made some nice torque. Definitely a get the job done type of motor, but not sexy. They burn oil, they run funny, not smooth, don't have a good exhaust note, they don't rev high. Yes they are easy to work on, but they aren't going to get killer MPG. Big Heavy car, big iron engine, at the end of the day it wont be that different from a 305 or 350. It would matter more how heavy your foot was on the gas. IMO, the 4.3 was just never right. Built from the SBC 350, but somehow that glory never transferred over. I just think for all the work and headaches that go into motor swaps, I couldn't imagine doing all that for an NA 4.3 v6.

 

[rangertom]

Most will be happy to know I decided against doing a 4.3 swap, I'm leaning on doing an LQ swap or the likes since reading about it on the forum. If I can get the same or better fuel mileage and from what I read i'll get better and have the power of a V8 with the newer engine then I think that's the way to go. Although the newest pick yard to open up around here has some nice BBO engines sitting in there and i'd love to stay original ( somewhat) and put a piece of history under thehood, with fuel prices I just can't justify that 🙁

 

[DRIVEN]

I think you'll be happy with the results.

 

[olds307 and 403]

The LS swap is the best of both worlds. The fwd efi swap is also supposed to be a huge improvement. Just get a 85 distributor and efi set up off a fwd 3.8. Simple bolt on, wiring would be the hardest part. Of course a TH2004R trans and 3.42-3.73 gears would not hurt mileage one bit and feel like a huge gain.