Hey, guys I'm in quite a pickle I have a 1990 bonneville sse and I want to make it a sleeper.
I want to know preformence parts can be used for this car if you could help me that would be great thanks.

What are your end goals? Do you plan on drag racing, road course racing, or something completely different.

How much power do you want to make? What other cars do you want to run with?

What skills do you have? Are you ready to change a few spark plugs? Are you ready to tear the engine apart? Are you ready to strategize and fabricate a full drivetrain swap?

Virtually zero performance parts for the Series 1 engines.

If you were to somehow put a supercharged engine in this car, it still would not be classified as a 'sleeper' due to there are already supercharged Bonneville'* mass produced. A turbo wouldn't make the classification either.

A "true" sleeper would be, putting a V8 in it, and converting it to RWD. Again, there are no 'kits' to doing this either.

"With a welder and plenty of money, anything is possible"

I suggest you find a different something that is more 'plug n play' vs complete CUSTOMIZATION.


You could take a full length 4 cylinder *-10 frame with suspension, axles etc. Take the 4 banger out, drop a Vortec 350 in it with a 4L60-E, then drop the Bonneville body on top of the *-10 frame.

Im fairly new to most of this and I'm grateful to have gotten a good explanation thanks. but I was also wondering what could be some good engines swaps with this car if there is any. Thanks again.

Series 2 L67 is probably the common (if you can call it that) favorite, and carries a fair amount of documented swaps on the internet. Built out, several have cracked 400hp while maintaining daily driveablity. For this level of power however, it will require a full engine and transmission build.

Ultimately, your best bet is to pick up an entire donor car to draw your swap components from.

It'* growing increasingly difficult to build a sleeper these days. many unassuming v6 drive trains are pushing over 300hp these days stock.

Thanks! This was alot of help could I possibly stick a 4.4l bmw engine in ? And what all components are used when fitting a new engine ? Thanks-

Anything'* possible. Like the others said above, it depends on how much work and fabrication you want to put into it. In this case you are talking about putting a 20+ year old longitudinal German engine in a 28 year old front-wheel-drive American car.

Even if the engine itself could be made to fit dimensionally and bolt directly to the existing transaxle, you'd have a lot of work to do getting the electrical and gauges and etc. to work together. All hoses would need to be adapted as well. You'd need to rebuild the transaxle to handle the extra power as well. That'* the sunny-day scenario. In reality, the minimum you'd need is an adapter-plate kit between the engine and transaxle, as well as a custom oil pan and flex-plate. This will hurt under-hood space. Then you'll notice that the BMW engine is an OHC engine, which means it'* taller than a OHV 3800. Now you need a custom tall hood . . . and now it'* not a sleeper any more.

While you're rebuilding the transaxle for all that power anyways, you may as well swap a L67 3800 supercharged in. First rebuild the L67'* transaxle to handle more power, then rebuild the L67 for the ~400HP mentioned above. This will take little creativity in engine-bay space and mounting, and the electrical and gauges and hoses and etc. will be much easier to deal with.

There'* no set list, and this type of swap (at least the L67 swap) is fairly-well documented on the interweb. Before spending a lot of any of our time time on the answer to this, it is important to ask: Do you have:

- thousands of dollars
- more thousands of dollars if you aren't doing the work yourself
- 12-pack of family size cans of elbow grease
- weeks of downtime of this vehicle

. . . to throw at this project?

I agree. A 1990 Bonneville isn't really worth the effort or money unless you HAVE a shitload of money to waste away. Otherwise, you are wasting your time.

Find a platform that you KNOW you can upgrade. For example, my *-10 has a V8 in it. Everyone knows they come from the factory with 4 cyls or V6'*. No one ever suspects I have a V8 until I go around corners sideways.

I once had that idea but my budget and cost benefit out weighted it. Serious power will only come from an engine swap. I live vicariously through adventurous people who have a dream. A turbo would require exhaust mods, a tune with trans work, etc. The Caddy 4.6 is a doable swap with some fabrications as is the SC 3800 with 13 second timeslips and smooth idle. Then you would have to upgrade your suspension and brakes. F. I. engine swaps and other upgrades without a donor car can be costly. My 1989 Buick Electra is mad and jealous of my 2016 Chevy Impala (6.3 zero to sixty) because it has 300 hp and is happy to rev to redline. I hate that the Buick is sad but there is nothing else like a fun to drive car to raise your heart rate and not want to cuddle later

Maybe your right about not wasting my time on this but reading that just made me even more compelled to try