GHOSTOWLGRID

1987 cadillac with an olds 307 v8.
What are some options for better performance?
The car has single exhaust, I was thinking about headers and trying to do dual exhaust.
is this TBI or carb? I was thinking of replacing the carb and intake if its carb. But the car has an ECM, is it tunable?
spark timing?

I'm not looking for much, just a little bit more kick out of it.
I know the trans has a limit so I want to stay under that for sure.
I don't have much knowledge about the older engines like the 307, 455, etc... I would like to learn.

olds 307 and 403

Unfortunately you have late swirl port turd 307. Less than 8 to 1 with tiny ports. Even Olds only got 200 HP in a prototype with the HO cam, shorty headers with a much better y pipe and cat. The A5 intake is the only intake that properly fits your heads. If you could find the HO roller cam and add Sanderson shorty headers with custom duals you could make 200 HP. Anymore a 403 would work much better, especially with the extra 70 ft/lbs of torque.

joe_padavano

Welcome, and I have to agree. The late roller cam, peanut port 307s are not worth spending a dime on. Assuming you are not subject to emissions testing, the cheapest, easiest, fastest way to improve performance is to replace the 307 with an Olds 350 or 403. Of course, at that point you may find that the 200-4R trans needs to be upgraded to survive, especially in a heavy car like that Caddy.

All small block Olds motors are externally identical, so this swap a a complete bolt-in.

GHOSTOWLGRID

would an edelbrock 600cfm carb improve the engine without damage to the transmission?
Not looking for much, just a little more kick.
I could combine this with the headers linked above.

joe_padavano

Your car uses a computer-controlled Quadrajet. The computer uses the throttle position sensor in the carb to also control timing, trans converter lockup, A/C compressor clutch, and other emissions controls. Changing the carb requires you to bypass the computer, which also means a new, non-computer distributor must be installed, and you must also install alternate means of actuating the trans clutch and A/C compressor. This is not impossible, as many others have done this, but it isn't as simple as bolting on a new carb. Note that the Qjet on the car now has an internal stop on the secondary air valve to limit airflow, since the 307 can't use a bigger carb.

The roller cam 307 was designed for low end torque and gas mileage in large heavy cars. It has tiny intake and exhaust ports because of this. The intake manifold is restrictive and changing the intake will create a port mismatch at the heads that will negate the change. The exhaust ports are similarly tiny and I'm not aware of headers that fit this chassis without mods (like you have to remove some bolt-on chassis reinforcement brackets, which I would not recommend).

Both of us have told you this is not a good engine to upgrade for a reason, based on personal experience.

GHOSTOWLGRID

I was thinking of a carb upgrade but I didn't realize it was that integrated into the computer.
My understanding of these older engines is very minimal and there is a lot of conflicting info when I try to read things.

Since there is a lot more to it, because of the computer, I'll wait to make changes, but it would be nice to learn about this and go full carb/dist setup.

Aguaros

No point. It wouldn't significantly boost power and you can't get much power out of a 307 because of the thin-wall casting. The 1985+ 307 can't really be built up from its stock form without dropping huge amounts of time and money into it, which the motor isn't worth. Best bet is to just yank it and replace it with an Olds 350, as it's a straight swap.

slantflat

I've got this same car, and while I wouldn't mind a little more oomph out of it, my concern is braking. If your brakes are anything like mine(lacking), I'd figure out how to stop better before going faster.

Although, for a big heavy car like this I find that it's quite agile. Something I wouldn't have guessed. Must have something to do with it's way over boosted power steering.

Destructor

Sell the 87 and get a 1977 - 1980 with the 425. If you still want more power exchange the 425 for a 472 or 500.

olds 307 and 403

A much better carb would be the Street Demon 625, has a dual bolt pattern, plus better metering and a non computer HEI distributor. Plus you can get brackets for it to work with your trans. If your current computer carb is working properly, the gain would be minimal at best. Bolt ons are fine like a carb or headers and duals plus will work with a 350 or 403 later on.

GHOSTOWLGRID

Surprisingly enough my brakes work excellent, the car stops very fast if I really press the brake, and it can lock the wheels easily.

I don't mind the 307, its good, but I do wish it had a bit more punch.
I picked the 87 because I like the interior and body styling.

What is a good affordable v8 swap? If I go full carb and distributor, I can eliminate the computer completely.
I was thinking of a TH400 trans, this a good choice?
I'm okay with poor gas mileage and no torque lock up, however I would want working air conditioning.
I can go electric fan and I don't know what drive shaft or rear diff to select.

I think the speedometer is cable that rotates off the transmission and the P-R-N-D-3-2-1 is on the column, I would like to keep these stock and working if possible.

What would you guys suggest for a beginner with not a boat load of money, but eventually I should be able to spend abot 3K at most for parts, I can do the rest myself.

I would like to get as much power as possible without going too radical on the idle and without a blower on top, all N/A power.

joe_padavano

Scroll up and read posts #2 and #3, where we suggested the easy swap.

That was answered in post #5.

Bulletproof trans but it will require a custom shortened driveshaft and a different front yoke to match the trans.

Again, addressed in post #5.

You don't need an electric fan. You will need a larger radiator. The one from an early-1980s Caddy with the diesel 350 would be a good choice.

Again, if you simply drop in an Olds 350 or 403, none of that changes. If you swap a TH400, the trans linkage still works, but gear positions will be slightly different.

Bfg

Don't do anything to it, just enjoy the car as it was meant to be! It's a Cadillac not a race car. Dig the seen with the gangster lean.

Aguaros

The THM400 wouldn't be a great swap on an Olds 307 or 350. No O/D, no lock-up, and it'll eat a lot of power. The other issue is that it's not a straight swap. Generally, unless you radically upgrade the engine, you shouldn't put a big-block transmission on a small-block engine. The THM200-4R can be rebuilt into a much better transmission too.

To get better performance, you'll also have to change out the rear diff.

An Olds 350 or 403 is really the best option, as they have good build-up potential and it's a straight swap from a 307, as they're pretty much the same engine aside from displacement. The Olds/other GM big-blocks require more work to swap in.

I'd say the 350/403 would be my limit, as doing much more would cost more and be more work than the car is even worth. The Cadillac Brougham is not a muscle car, so it won't be able to handle much of the speed that may come with a bigger engine anyways.

GHOSTOWLGRID

So me finding a TH350 and a 71 olds 350 rocket would work.

Then All I'd need to do is rebuild the engine with a good cam, and do up the drive shaft with a good posi rear diff?
I know most of this has probably been asked many time before, I just have no experience with older v8's until I start swapping things.
I find a lot of info, and everyone does so many different things, there is a lot to choose from.

I know its an awesome cadillac, I like keeping it original, but I want it to have some good hidden power.
The more I look into this, the more I want to pull the 307 and do the swap.

As long as my A/C can still work, I'd be happy going full carb and distributor with no ECM.
The only issue is that auto climate control thing in the dash, I would have to figure out how to keep that working.
(Set temp and it auto runs the vents and blower and A/C)

Edit:
What if I came across a built olds 455 with the turbo 400 trans?
That should still bolt right in?

Aguaros

Keep the THM200-4R, just get it rebuilt/upgraded to handle the increased power. This way you can keep the driveshaft and save yourself some work. Just make sure you know what you're doing the whole way through this project, because a mess-up can cost you a lot of money and time. Engine swaps are not for beginners with little to no experience. This is important because you're dealing with a car that isn't worth much. Keep the expectations realistic too; I would keep my project from getting too grandiose, because honestly, $3,000 isn't really a lot of money for stuff like this. You may be surprised to see how quickly costs will rise.

Also, just remember, that despite whatever performance upgrades you do, the car itself will still have limits inherent to its design. You won't be able to blast away at 110 mph without damaging/destroying the suspension components or brakes and you still won't be able to handle the twistys too well. I once owned a 1977 Cadillac Sedan DeVille, a 1988 Cadillac Brougham, and now own a 1984 Olds 98 Regency sedan (basically the same car), so I know these 1970s-1980s B-C/D-bodies pretty well.

No it won't. That's a bit more work and money. IMO, an undertaking like this isn't worth it on an '87 Brougham. Stick to the Gen 2 Olds small-blocks for the best results.

GHOSTOWLGRID

Ive done engine swaps before, so I understand the time and work will be a lot. I'm just not famaliar with the older v8 engines.
Its been mostly fwd v6 engines for me.

As far as the cost, its optional but the lower the better.

This car has a lot of life in it. The only rust problem is my drivers door, the rest is fine so I dont mind spending the time on the big swap.

I just dont want to go through the headach of rebuilding another automatic is why I like the swapping idea for the bigger trans.
I have had mount brackets welded before, i can do that again if needed.

But as far as clearance, will the 455 and the 400 turbo trans fit?
The mounts, shaft, and other supporting mods can be dealt with.

joe_padavano

First of all, any small block Olds motor is externally identical to the current 307, so it is a direct bolt-in replacement. Second, the TH350 is the same overall length as the original 200-4R, so the driveshaft stays the same, but the rear trans mount location is different. Unlike earlier GM cars, the 1977-1990 full size cars used different crossmembers with the different transmissions to account for this mounting pad location. You cannot simply slide the trans crossmember forward the way you could on an older GM. You must use the correct TH350 crossmember. The TH350 was used in these cars in the 1977-1979 versions and behind the Olds diesel in later years, so they are out there. Ironically, the TH400, while longer overall, uses the same crossmember as the 200-4R.

The Olds 455 is also externally identical to the 307 EXCEPT that it has a taller deck height. This means that it bolts to the 307 mounts, but the engine is taller and wider by about an inch. It will still fit, but you need to use the correct big block Olds exhaust manifolds. The 307 accessory brackets require minor mods to accommodate the taller deck height. This swap has been done many times.

Aguaros

Joe's post right below yours sums it up pretty well.

Thing is, an Olds 455/THM400 swap would cost more, as it's not a complete straight swap like another small-block would be. Swapping in another Olds small-block is a much better move. Like I said before, with a swap on a car like this, I'd keep it relatively simple, and a good Olds 350 is just that. The big-blocks will work fine, but it's a costlier swap because the engine won't work with some of the 307 brackets, exhaust manifold, etc. Also, 455s can be harder to find (especially earlier ones) and will cost more to buy than a 350, which is still pretty common and prices aren't too outrageous. There's a lot more support available for them too and parts are cheaper/easier to get.

I know you said you don't care about gas mileage, but an Olds 455 will be a huge gas hog (8-11 mpg). Take into account your '87 Brougham only has a 20 gallon tank (the 1988s got the 25 gallon), so your cruising range won't be good at all. I wouldn't look into big-blocks with a small tank like that.

Like I said, keep the swap pretty simple, because anything too out there on a car like this isn't really worth it and costs will get out of hand fast. The Olds 350 is the most sensible and economical replacement by far; you'll find that it'll suit your needs very well. A good Olds 350 can give big-blocks a run for their money.

Harold318

I have a 87 Brougham. Well its my uncle's car and we have had a headache finding the right 5 hole vaule covers gskets with the guy never telling us the motor. We are still stuck between a 307, or 425 from what people are telling us. And we are trying to put the cork gadkets we did find from a 307 on. Just need to know what steps to take. And we have the good gasket glue. New here so once i figure out how i will post pictures of the car

joe_padavano

Welcome. The right "five hole" valve cover gaskets are the ones with ten holes. They are exactly the same valve covers as the earlier ones; Olds just didn't drill the other five holes to save a few cents per car on the cost of the bolts.

The casting number above the water pump will tell you exactly what motor you have.




The 425 Cadillac motor went out of production in 1979. The unrelated 425 Oldsmobile motor went out of production in 1967. The only motor installed from the factory in a 1987 Brougham was the 307 Oldsmobile.

Harold318

thanks for your help. Thats the best information ive had in a year. Thanks