: 90 Brougham Motor Swap: LT1 or 455 Rocket

08-11-07, 12:24 PM
For all owners of 86-90 Cadillac Broughams, we all know that the 5.slow L is the worst engine Cadillac has ever used. I know a lot of people out there have considered swapping the motor out for bigger motors. I own a 1990 Cadillac Brougham and I want to do a unique motor swap. I'm thinking about using an LT1 straight from a 95-96 Corvette. But lately, I've been looking up on Olds/Pontiac/Buick 455. This motor has a lot of potential and is a LOT cheaper than the LT1. The LT1 in a 1990 Brougham is pretty unique to me because no one's done it. Of course, the initial thought is to buy a 95-95 Fleetwood, which is the car I've always wanted(still want it!!), but I also like the sound and power of old school muscle. The car is kinda in between old school and new school. Any suggestions?

08-11-07, 01:37 PM
455 is a great motor, but is $$$ if you find one that is in good shape. My father has a stage II 455 in his '70 Electra Convertible and it is a great torque monster.

It depends if you want to deal with a carb'd motor again.

The most economical solution would be to do a 350 TPI swap like Destroyer did on his 1991 Fleetwood. You might be able to find a 355/383 TPI for cheap?

I give you props for this idea, I have always wanted to do a LT1 in a '90-92, but never had the time. Go for it!!

08-12-07, 07:56 PM
I love BB's, but they are pricey, in the initial cost and fuel dept. The LT1 is a great engine and can be easily found for $300-$500. I picked up a whole parts car for $300 with 4L60E and LT1, disc rear end and 12" front brakes. I call that a killer score. The LT1 tuned will do well in that car and a sweet swap. I would lean that way instead of going old school. But, if you go old school, by all means, fuel inject it!!!

And a BBO will trash any trans you put in it short of a 4L80E or THM400/3L80. So hands down, $$ is the LT1.

08-13-07, 11:34 AM
That's what's up. I'll get my money right and keep my eyes open. :)

08-15-07, 12:03 PM
First of all, the Olds, Buick, and Pontiac 455s are three completely different motors. The only thing they share is the bellhousing bolt pattern and the distributor cap. The Olds will bolt in using the 307 motor mounts; the others require custom mounts. Any of the three will shred a stock 200-4R transmission, though this trans can be built to withstand the torque. The least expensive way to do this is to find a running but rusted full size Olds from the 1970s. Cars like this can be had for $200-500. Another choice is an Olds 403. This is a small block and is externally identical to the 307.

08-15-07, 06:08 PM
Yup, but those later year 200 4R's were dual bolt pattern, so shouldn't be a bolt up issue. But the trans destruction when you nail the gas the first time has to be addressed....

Olds is my BB of choice there for ease. Pontiac is my preferred 455, but the Buick is very fun too (largest bore, shortest stroke, revs like crazy). Pontiacs are my overall favorite.... Diesel like torque and can move freight trains if needed....

09-05-07, 01:29 PM
I found an LT1 at the junkyard right around the corner from my house! And it's cheap! Now I gotta find a 4L60E tranny to match it. Now I need to know what issues I will face to do this swap. Preferrably wiring issues. Any tips?

09-06-07, 05:41 PM
93 was last year for 4L60 (not E) in cars and 4 bolt tail
94 was 4L60E, without PWM TCC modulation and 4 bolt tail (can add PWM solenoid if you so desire)
95 was first year PWM and 4 bolt tail (can remove and plug PWM solenoid if you so desire)
96 has removeable bell housing and 6 bolt tail section

Make sure you run appropriate PCM tune for the trans you have, make sure the tuner knows exactly which you have!

A truck 4L60E might be a decent one, they are probably rebuilt more often. I just pulled one from a 95 cop car that has been rebuilt, but I still have no idea if it is good or not (painted a very light green even...). The Suburban ones will have the HD parts similar to a V4P tow package car, so if you want a drop in one that should be robust, that is a good choice. And Suburbans from 96-99 ALL came with either 3.42's and 3.73's. 4.10's only on 3/4t and then they got 4L80E's. You can also get any truck trans from 96-present, 4L60E or 4L65E, doesn't matter, they all work fine.

Talk to Shane at CPT about the differences and what is a good core if you are gonna rebuild one.

04-16-14, 06:05 PM
Did you get it done?