Hey everyone,
well I just bought my 1989 firebird about a month ago , and since than I have been doing the minor fixes on the brakes and such in order to pass safety.
What i'd like to do next is get rid of that PUNIE 2.8L!!!

I'd like to stay away from the shortblock 305's bc of the gas prices, so... would a 4.3L swap be a peice of cake? I have never personally done an engine swap, but know a good amount about engines and such. These are the main thoughts running in my head...
1- Will I have to change the transmission aswell?
2- What parts do I have to get to accomidate the 4.3L?
3- Shocks or anyhing needing to be changed?
4- What are the MAIN things to keep in mind when swapping the 4.3L in?
5- I was hoping to get a 4.3L from an Astro, or a Safari. Is that possible?

thanks alot guys, really appreciate the help

Jared

PICTURES OF ENGINE FOR REFERENCE

 

Welcome aboard thirdgen.org.

You will have to change the transmission. The 4.3 uses the same bellhousing pattern as Chevy V8's.

It isn't the parts so much as the fabrication. There are no mounts available (to my knowledge) or exhaust. Both of those will have to be fabricated.

Shocks are fine. Springs will be marginal, but you can probably get away with the V6 springs.

The main thing to keep in mind is the 4.3 wasn't used in 3rd gen chassis.

You can get a 4.3 from an Astro, Safari, S10, S15, etc.

This is probably the least supported swap for our cars. Far from a piece of cake.

 

How about a 3.4?
Id really like to shut my buddy up and beat his 95Buick Riviera 3800Supercharged . He really wants to show me up. Lmao

 

doesn't the 3.4 need the ecu and some other various parts? Its all crap you can buy because its all made for the 3.4 birds?

 

So a 3.4L would be a good choice?

 

The 3.4l is a reasonable choice. The information about what's required to get it done can be found on the V6 forum.

Whether it will outrun a supercharged 3800 - probably not.

 

Hey there, don't discount the 305 for mileage. here are a couple of quick links for you regarding the mileage of each.


Chevy Astro with a 4.3
http://www.fueleconomy.gov/feg/bymak...olet2005.shtml

Pontiac Firebird with 305
http://www.fueleconomy.gov/feg/bymake/Pontiac1988.shtml

The 305 gets better mileage than the gas sucking 4.3. I switched mine to Royal purple synthetic oil and E3 plugs and I still get 27 miles on the highway and 18 in the city.
The annual fuel cost in this chart is based on gas at 4.09 a gallon. It's cheaper to operate the Bird with a SB as opposed to the 4.3

 

KED85 did up a super sweet tech article on the 2.8~3.4 swap boogie. I've done this swap, along w/a 3800II swap in my old bird....... along w/a 305 swap (but that's besides the point).

For ease & affordability, the 3.4 is the way to go, basically swap over upper intake, tb, front cover & accessories (depending on which accessories youo want). yes, the short short short list.

THe 95 3800 s/c came w/200hp, the same amount as the 3800 II n/a. just some food for thought

 

just go 350 put something like a big blower that won't let you fit a hood and can you use something like a 200shot with one of those?

big drag slicks and golf cart tires in the front.

Seriously, 3.4 or 305. Make sure you can throw a 5-speed in it.

 

I'm actually working on it. I rolled my '00 blazer and always wanted that 4.3L in my '85 camaro. so I'm probably going to pull the 2.8 out today and start prepping the engine bay. cause I'm transferring the AC parts too. it's looking like the engine mounts will fit. and I'm using as much of the blazer parts as possible including: radiator, all AC parts, instrument cluster, transmission, all computers and wiring. I'll miss the 5 spd and I know poeple will complain about a 4L60E in a camaro but oh well it's what I've got.

the powersteering lines are a direct fit but I'm not sure oh the fuel system it going to work yet.

so to me if you've got a complete donor car it looks possible. but I'll let you know if it's worth it

 

Getting back to the 4.3 swap,I know it's possible,and I truly believe that it's feasible.As 57 said,you'll need a V8 or 90 degree V6 trans.Let me state that I have never seen it done,but I'm 99% sure that you could get the entire engine mount assembly from a 88-98 4.3 truck,and it will bolt in to the V8 frame holes,with the trans in the stock position.Check them out.
I personally would do a V8 if I was going to the trouble,but I could see a 4.3 as a fuel efficiant yet sporty option for our cars.I'd love to see it done,and don't think it would be as bad as some people say to pull off.

 

You may want to get some car chevy V8 motor mount brackets that bolt to the block. I'm not sure about S10s, but I know the full size pickups have different brackets that put the engine higher off of the frame. Some Camaro or Monte Carlo V8 brackets should do the trick.

 

Advance adapters makes some 1/4" steel plates for SBC-into-(S-10s built with a 4.3) I used them when I stuck a 4.3 into a third gen, install them the other way, since you now have the exact opposite issue from the S-10

 

I think GM made a 4.3 V6 third gen, and there is a 4.3 V6 third gen sitting in front of my house right now. I think the only fabrication involved in installing it was making the motor mounts (which Atilla already pointed out an alternative for doing), and making the long tube headers (which wouldn't be necessary since you can just take manifolds from another vehicle that will fit).
I believe the valves on 4.3 V6's go EIEIIE, am I correct to assume that all 4.3 V6 heads are like this?
For accessories, you could just take them from any V8 third gen, the only problem I can think of is that you might need to lengthen the power steering lines.
I don't see any reason a 4.3 wouldn't be an easy swap.

 

I thought the 4.3 blocks were basically just SBC's with two cylinders lopped off? You guys sure tehy're not interchangable with all the v8 parts and v8 mounts?

 

The V8 mounts will bolt up to the block, but because the block is shorter it places the mounts in an odd position on the frame.

I suppose you could re-drill the holes and make them line up?

I don't honestly know. No one seems to have taken a picture of this swap.

 

My question for this whole thing is why. If you are already pulling the engine, getting new mounts and all this stuff, new wiring, new exhaust and all these new parts, why would you not just put an engine capable of pulling the car around in it? The ONLY v6 that can do that is the TTA 3.8. Otherwise just stick a sbc in it with a cheap but effective EFI setup and either a 700r4 or a t56. Both will get WAY better gas mileage than any v6 will in these cars. Performance will be better as well.

I just don't see the point in doing all the hard work for less payoff. And please don't say different. The only thing different you will have at the end of the day is a slower car with worse gas mileage.

 

Here's a pic. I don't know why you think fuel efficiency would be so bad. It would be a lot better than a SBC. Sure, they also make less power, but the one in this pic makes a little under 350 hp, and that is mostly stock parts, except pistons, cam, carb, headers, and heads (the heads came from a 229, to put the CR around 14:1).

 

I am gonna be going through this swap soon myself. I personally wish the Nay sayers wouldn't post. If someone wants to put a 4.3 in thier car, its thier choice. Quit giving them a hard time. ITS THIER CAR AND MONEY NOT YOURS.

Yes it is a hard install, yes its not fuel effecent(mayby, the engine Im using has proven to me at least 25 MPG on occasion in the past) but dangit, its our cars. Those that want to slam, or insult go somewhere else and slam. it helps us not.



The engine I have is off of a 89 Astro and its going into an 89 Camaro. from what I understand all that has to be fabbed(or adjusted) are the moter mounts and the exuast. no biggie

 

they have the right to nay say, you can't do anything about it, but you can refuse to believe them, or take to heart what they say. I'm one of them, because I've been there, done that, and I'm trying to keep you punk kids from repeating my costly mistakes. But if you ignore our sound advice, expect us to laugh at your foibles.

 

funny thing is, Im not a punk kid, I have put the 4.3 into more vehics that I can remember. I currantly have one in my astro that makes most V6's wet thier pants. Been there done that. I Just wish people would just knock it off it they have nothing constructive to say. If it dosnt help the person just go away

 

I love the 4.3, I'm on my 4th. They have a lot of good uses, but this isn't one of them. Maybe if GM had been smart enough to build these cars with the 4.3.. As for gas mileage, my '94 W/T 1500 with automatic and 3.73:1 axle got 26 mpg a few times, and averaged around 23, while my '89 S-10 4.3 with automatic and 3.42:1 axle averaged 28 mpg at 70 mph. On the other hand, my '78 Camaro 350, with 700R-4 and 3.08:1 axle, got 26 mpg on a regular basis.

 

my 91 firebird has a 4.3 in it, it really isnt that bad of a swap, and you cant say im saying that just because i a pro or anything like, ive only done like 4 swaps. i think its an excellent idea to use a 4.3 but i also think its better idea to use a 350. the main issue with the 4.3 into the 3rd gen is that you need to drill new holes in you cross member to make up for the 6 inch shift backwards of the mounts. you can fit 3 of the 4 holes of the mount onto the crossmember, the fourth one is off of the crossmember( yes this means it barely fits). you can use a small block tranny, a 2.8 or 3.1 or 3.4 trans will not work. it definitly would suck using a fuel injected 4.3 (as i did) because its much easier to wire in a carburated motor. and if you use a newer motor you have to deal with passkey and stuff but very doable. exhaust wise you will need something custom, i would recommend headers becase i dont think you can get manifolds to fit a custom stockish style y pipe on anyways, i was fortunate here cuz my 4.3 is turbo'd so i have a single running down the passenger side and is easy that way. i had taken the starter off and the coil off (when i was dropping the motor in and it was still a tight fit because of how far back the mounts are to the firewall. any other questions for me you can pm me if you plan on doing this

 

im not sure what you mean by pulling the car around it but i completely with your logic here, i got my motor for cheap and its a typhoon motor, 4.3 turbo, thats the only reason i put a v6 in it, and i tell you what i miss my 350 i had in my car before the 4.3, even though my 4.3 is a bad mamajama

 

Not true. No 4.3's in 3rd gens from the factory.

It's the fabrication that would be very difficult for most swappers.
"Fabrication" and "easy" shouldn't be used together.
I don't see any "nay saying" in here. I see reality checks, that's all.

One person's "easy" is all too often another person's "hard". You are admitting it is hard. The OP used the words "piece of cake", which obviously it is not.

I would put the difficulty of installing a 4.3 into a 3rd gen f-body at the same level as installing an LS1. The total cost may not be at the same level, but the fabrication difficulty would be. I'm not saying "install an LS1 instead of a 4.3", just giving an assessment of difficulty, which is what this thread started about in the first place.

 

Notice how I said 'a' 4.3 third gen:

https://www.thirdgen.org/forums/hist...z-concept.html

 

Concept cars and one-offs don't count.

The factory concept shop also put a 350 Ram Jet in a 3rd gen, but that doesn't mean GM "made" a 3rd gen with a 350 Ram Jet.

If you're talking about concept cars or one-off specialty cars, just say so.

 

Could you post pics of the motor mounts and exuast setup please?? those would be helpful to those of us who want to do this swap

 

unfortunately i didn't think to take any pics of the mounts after i installed them and before i put the motor in them(they are factory 350 mounts with new holes i drilled i think 6 inches closer to the firewall), i might be pulling it out this winter to put a t56 in it or at least taking the whole top end off however and will definitely take pics then, and like i said its a turbo setup so i don't know if it will be helpful to look at the exhaust but i could still take a pic of that for you.

 

any and all pics are helpfull, gives me a better idea of what Ill be lookling at this winter when I do my swap

 

are you planning on a carb or FI swap. mines coming out of a 00 blazer. I'm going through the process now. I pulled all the wires I don't need out and made a new harness and got it to start again. I'm also swapping the AC system so I had to stretch the evaporator box out 2 3/4"s

I did find a set of engine mounts that should work for $27 on summit

and another issue is the fuel system. the 2.8 is up to 14 psi and the FI 4.3 needs up to 65 psi so I'm going to see what I can salvage from the blazer but first I need to find a place to put about 30 gallons of fuel.

 

Im gonna do a full FI swap, So I will need to move the Wiring and the Fuel pump as well.

 

you can use standard 350 mounts, just drill new holes and as for the fuel pump, i doubt the pump in the blazer will fit in the sending unit for the thirdgen, however worth looking at. if it were me i would probably just get a walbro 255 hp from online for $100 and call it a day

 

i got a 1991 firebird with a 3.1 and im thinking about doing the 4.3 swap as well.
as for the trans i got a turbo 350 my question is the th 350 is shorter than my 700R4..will the b&m conversion kit work with the 4.3L set up? and my fuel pressure is it to much for a holley 4 barrel?

 

honestly my old 4.3 s10 had **** poor gas mileage, id have to agree you might be better off with a 305 but if you got 4.3 motor give it a try... Honestly my friends 305 3rd gen got much better mileage then my 4.3 s10 but the truck body and gears will play a role.

 

im gettin ready to get a 84 S-10 with a built 4.3L its got a pretty good size full roller cam, and oversized forged pistons, with a holley 4 barrel, the motor runs real healthy and, you never see a 4.3 in a 3rd gen and i think its pretty cool, im not looking for gas mileage, my 3.1 in it right now adverages 28 mpg on the highway, but im wanting to keep it a v6 without going through alot of problems like alternating my wiring harness....and with the 4.3 its pretty basic and simp.
and when i out run the v8s there gonna want to see under the hood and its going to be a little 4.3 lol

 

I got my 4.3 in my camaro and trying to get it started. guess I have some wiring issues, it'll fire up at first then die and won't restart and I don't know if it's my wiring or some anti theft device.
I did manage to swap the pump from my blazer, I had to take the assemblies apart and use just the pump itself from the blazer into the camaro's assembly. but the interior is now just a mess of wires. but at least I do remember what most of them go to

 

can you post pics of you car with the 4.3 in the car...what kinda tranny you runnin?

 

My '89 S-10 4.3 repeatedly got 28 mpg at 70 mph. Not what I'd call **** poor. When the '02 sensor failed it dropped to 19, but a new sensor fixed that. Yes, mine was lowered 2", but I had 235/60R15s on 15x8" wheels, and had changed from 3.08:1 to 3.42:1 rear gears. And third gend have more frontal area than my S-10, being several inches wider than an S-10.
I had a '94 W/T1500, fullsize with the 4.3, it averaged 23 mpg with a best of 26.

 

I'll work on getting pics up. I finally got it running once and I walked around to check for leaks and shut it down, now I can't get it to start again. I think it's that stupid passlock system.
and I'm using the 4L60E that came with the blazer. 4 spd automatic

 

 

I'm Glad you get such great gas mileage, but are you sure you don't have the old 2.8 v6? I've had many a s10's between myself and friends and none of them averaged anything near 25mpg. Maybe if your talking STRAIGHT HWY driving you'd get mid 20s but please stop kidding yourself 28mpg with any mix of city driving is straight BS.. For any normal driving circumstance you should expect 17-22 mpg and with that kinda of gas mileage i would much rather have a 305 or 350 in my camaro...... just my opnion why waste your time with a more time consuming swap when you can drop in a V8 and get the same gas mileage? But like i said in my original post to each his own and if he chooses to drop in a 4.3 awesome.... can't wait to see how it works out..

 

my 350 in my '88 suburban has never gotten better then 14 mpg, that 4.3 in my blazer averaged about 22 and straight highway saw 24-26. the 2.8 that was in the camaro was getting about 16 city 24 highway. and that 2.8 gave me nothing but trouble the whole time I had it. according to my Gtech guessing the weight around 3k it said it was putting out about 76 hp. that 4.3 puts out around 200.
and with this swap it cost me around $300 and I'll have auto lights, an overhead console with compass and outside air temp, cruise control, air conditioning, and an OBDII port so it's easier to program
all that's left is the exhaust and a little wiring on the lights

 

Let me answer this for him. Yes he is sure it has a 4.3.
I don't know why everyone thinks their cars are so inefficient, when my LG4 car was 100% stock I could get 24 mpg sometimes, even better after I installed longtubes and removed emissions crap, a 4.3 should be even better.
Think about it, a 4.3 is 25% smaller than a 5.7, so, it will burn less fuel and make less emissions, but less power also.

 

nice work i like how it fits and it looks alot like a factory production car where everything is takein care of under the hood tell me how good it run and drives when you take it on its first test drive

 

ive had a change in mind...im wanting to keep my 3.1 transmisson with the 4.3 motor, do they make an adapter plate to where you can bolt the 3.1l to a 4.3 or v8 motor?

 

You need to change it back.

 

I'm a professional automotive machinist, I rebuild engines for a living, so my ability to tell a 4.3 from a 2.8 cannot remain in doubt. The 2.8s don't get mileage, in any app. A 2.5 S-10 can average 28 mpg in city driving, and nearly 35 on the highway. But not a 2.8, not even in a Fiero. Anyone who isn't getting 28 mpg at 70 mph from a stock '88-'95 4.3, in an S-10 or F-car, needs to PM me. I'll get you straightened out.

 

just to throw this in the mix, i have been driving my 87 2.8 5 speed bird for 5 years everyday. randomly one day i decided to see what the best mileage i could get on one tank of gas was, now mind you i was driving absolutely ridiculously, mostly in the city and some on the highway and i got 26 mpg. as for my average on every other tank i drive i usually get just about 20-21 and because i have a need for speed(in my 2.8) sometimes i get as bad as 16-18 on parts of a tank. i would say a good range for my 2.8 is 18-23( that is probably the absolute limits for driving a car normal)

 

im sorry i donr have any input really on what my 4.3 gets but i did find this site that has vehicles mpg estimates on it...http://www.fueleconomy.gov/feg/findacar.htm , also i thought it was interesting when i clicked the link to compare to the original window sticker