I am getting a 2,8l auto 1986 firebird for 800 bucks, I want some peppy power but good mpgs. A 3800 swap sounds badass as I can boost down the line. How do you go about swapping a 3.8l into a third gen?

 

the 3800 is a 90 degree V6 I believe, so it’s not compatible with the stuff for the 2.8 which is a 60 degree V6. I was considering it at some point but stopped when I realized it was just as much work as a V8 swap.

The 3.4 V6 is a bolt in swap, as is the 3.1. You can boost the 2.8 if you want, but you wanna make sure it’s in good shape before you do that lol.

 

Is your goal a clean driver swap, or a dirty racecar swap? Like KITT said, a 3.1 or 3.4 is the easy option, and will be the cleanest outcome on a cheap budget. If you have a full 3800 driveline and don't care about things like gauges working, then let 'er rip bud.

 

I saw a ~ 1965 chevy ii that had a ~ 1995 FWD 3800 mounted lengthwize for the RWD- do not know what tranny was used,but i think the FWD 3800 has same 60* bellhousing as 2.8, You will be on your own for lots of small parts and details on the swap.

 

For what its worth, the 3.8 FWD & RWD blocks are the same. I put a short block from a 2007 Buick in my '97 RS during Covid (it's my DD, bought it in '98). The only thing you need to be careful on is chasing the threads for accessories and mounts, as it's an iron block and some are exposed and will be corroded. The donor block was an auto and my RS is a T5, so the flex plate and harmonic balancer had to be swapped, as well as the intake, oil filter assy etc, etc, but it was well worth it. Got an engine with 70,000 miles for $750 delivered to my door with a 6 month warranty.
Mike.

 

I think it's doable; GM put the 3.8 in the 4th gen which should share enough architecture and parts to work the same, in a 3rd gen. I'd acquire all the 4th gen parts if I were doing the swap. HOWEVER.....

You're getting a ~200hp engine and doing a lot of work and part$ gathering for 200 hp? Not worth it. But "I can boost it down the line." You CAN...but then you'll have the wrong compression for boost, you'll have spent the time and money to get and install the booster part$....and for all of that, you'll have ~250hp with detonation, possibly. Not worth it. I know it sounds/feels like a cliche' but put in a V8. Worth it.

 

My thoughts exactly. Sure the LS swap is “overdone”, but there’s a reason why. I would just daily the V6 until you’ve got the time and funds for a good V8 swap then go through with that.

 

I have a 1984 belinetta with a 2.8 ... I also have a 1994 lesabre with a tuned port 3800 V6. With the flywheel for the 2.8 bolt to the 3800 ? Why would I need to change the front harmonic balancer?

 

Do a part number look up if you don't believe me.

 

i am.not saying I dont. Just asked why I will need to change harmonic balancer. Will the 2.8 motor mounts bolt right up to that 3800? I probly don't have resources to know part numbers that's why I am asking info on here. That 2.8 is a basket case and my buick has a rotted sub frame but a great engine.

 

You will also need a different intake manifold and associated parts, exhaust manifold and y pipe (I went with headers), oil pan and pick up, oil filter mount, engine mounts at a minimum. I'm not sure if the accessories will swap over either, or if the ECM will work.

Most of this stuff you will need to get from a '98+ 3.8 Camaro or Firebird. Part of the problem is the intake and exhaust point in the wrong direction when using a FWD motor in a RWD application. You will see this when you take a good look at your 3.8.
I had to swap most of these parts over just going from a 3.8 FWD to a 3.8 RWD.

In any event, I would not call this a worthwhile proposition. You would be better off to buy a 2.8.

Oh, and it just occurred to me you probably will need to swap the gas pedal some how as the '94 is probably drive by wire.

Mike.

 

some GM Australia "Holden" cars mounted FWD 3800 for RWD with air intake facing back

 

Those interested in RWD installations of late model(88 up) of 3800 should have a look at the Holden(I looked at several youtube vids) earlier installs had same intake manifold as you would see on a 1990 Oldsmobile,but later models appear to have unique manifold.Different steering pump and AC is mounted along with Bosch alternator.Deep fan shroud suggests belt -driven fan,but there is an E-fan in the shroud.Some of the Holden cars with the Buick 3800 have optional Holden 308 v8: native Australian design similar to a small-block Oldsmobile v8