Cadillac 4.5 into '88 Grand Prix.

[2.8 Grand Prix]

Hey,
I found a 1990 Cadillac 4.5 V8 with 95k miles. I would really like to put this in my Grand Prix. My question is, will it fit? I looked up the specs on both cars, the Caddy is wider by 1 inch. Is this going to prevent me from doing the swap? It comes with the transmission, harness, and computer, all for $150.
What would I need to do to get this to work?
I think for a "custom" Grand Prix, this would be great. Plus, I'm not finding any 2.8, 3.1, or 3.4 engines around here in my price range with these kind of miles. Any quick response/suggestions/ideas will be apperciated. Thanks!

[robertisaar]

you CANNOT be serious...

those 4.5s were bigger boat anchors than the damn 3800s...

[2.8 Grand Prix]

Yes I am.

My friend has an '89 Coupe De Ville that does really quite well. The Grand Prix is 400 lbs. lighter too. This is not a car for fuel economy or street racing, this is a "custom" car. I have every intention of making this into a one of a kind Grand Prix.
I just want to know if it will fit. I will do all the work, and I can do some minor modifications if needed. If this will 100% not work, I will drop it. I would really like to do this swap. Thanks!

[Raffaelli]

Hate to break it to you bud but a 4.5 is hands down rubbish.

Garbage when they were new and garbage now. $150 is tempting, but its a no-no.

Come on, aluminum block iron heads? The oil sump/ pressure system is a band aid joke, the computer has wayy to many auxilary "features" to try to crack. Its not really that powerful. (155 HP).

And, never ever once seen a cadillac not leak oil....

[SappySE107]

If you are going to change your mind every day on what motor you want to put in, I suggest clubgp or w-body.com for advice.

[IsaacHayes]

If you want caddy pushrod v8, I'd do the 4.9 before that motor.. At least it was all aluminum and had more power. My 3100 has 160hp stock lol

[2.8 Grand Prix]

I am not changing my mind each day, I am just trying to find a cheap powerplant for my budget "custom" Grand Prix. I would rather have a 2.8, 3.1 or 3.4, but I can't seem to find one for under $250 with less than 150,000 miles. If I could get my hands on a wrecked '88-96 Grand Prix, Cutlass Supreme, or Beretta/Corsica I would jump on it.

I am just wanting to either repair my exsisting 2.8 or find a good-running, cheap 2.8, 3.1, or 3.4. Once again, if anyone has an engine that I could buy, let me know, Please! Thank you.

[robertisaar]

clubgp or w-body.com

thats kinda harsh, mentioning w-body and clubGP in the same sentence...

[Raffaelli]

Heres a tip,

Look for engines in minivans (eg Chevy Venture). Nobody wants minivan parts, and Junkyards know this. They may be cheaper. But are a pain to pull.

Just an idea.

[2.8 Grand Prix]

Not just an idea, that's a great idea. Nice one!

The '91-96 Lumina APV, and Pontiac Transport had the 3.1/3.4, and the '97-05 had the 3.4/3.8, so I think there are a lot of options. Thanks man!

[robertisaar]

Not just an idea, that's a great idea. Nice one!

The '91-96 Lumina APV, and Pontiac Transport had the 3.1/3.4, and the '97-05 had the 3.4/3.8, so I think there are a lot of options. Thanks man!

91-96 had 3.1/3.8 and the 97-up were 3400s...

but at least you were close.

[SappySE107]

Those are iron head 3.1s as well. The minivans have a bigger issue with the rear head since the van retains more heat in the engine bay. The 97-99 have the worst manifolds too but that is nothing considering you are replacing a 2.8.

[2.8 Grand Prix]

Ooops! Oh well.

Alright, I'll keep that in mind.

[LeftVentricle]

Little bit of clarification on the Caddy motors. The 4.1/4.5/4.9 were all aluminum block and iron head. There were a couple of year-to-year difference in power, and differences depending on application. The 1990 4.5 is port fuel injection, as opposed to the '89 TBI, and as such makes more power—180 hp and 245 ft-lbs. The 4.5 used in the Allante had a different intake and made about the same power as the 4.9 that replaced the pedestrian 4.5 starting in '91—200 hp, 275 ft-lbs.

I'll contest the "boat anchor" comment, since Fiero guys have reported little to no change in weight distribution after swapping from their stock iron head 2.8. True, they're a little underpowered for their size, but not much else makes that power stock-for-stock except for the oft-maligned L67.

I would go ahead and get the 4.5 and its transmission, since it's such a low price. I would then acquire a crank, rods and pistons for a 4.9, since the 4.9 is a stroked 4.5, and rebuild it.

EDIT: The '96 U-vans had the 3400 as their sole engine choice, the first car to get one.

[asylummotorsports]

https://www.car-parts.com

Shouldn't be hard to find an engine that would do the job.