: fuel injected 350 into 85 coupe



jak89
08-15-11, 07:40 PM
Alright so im new to the v8 world i've worked on engines before but only inline 4 and 6 cylinder nissan engines. I no longer have any of those types of cars I've moved on to the v8s

With that said I know nothing but the very basics about v8's and cadillacs,I want to put a injected 350 in my coupe to replace the 4100

So my main questions are will a injected 350 bolt up to the 4100 tranny, and yes I do know about the power limits of the stock drivetrain on this car but thats further down the road

also I need some info on hooking up the little things like fuel lines,if the fuel pump needs to be bigger,what I would have to do to hook up the alternator,and things like that

I was also wondering if the wiring harness for the motor just hooks up to one ecu so that I can just put the new harness and ECU in?

cadillac kevin
08-15-11, 07:56 PM
I'm not sure whether you mean a tbi 350 or a vortec 350, but either will bolt in (given you get a set of chevy motor mounts for the 90-96 fwb. the 4100's ecm will not work with the 350, or any other motor. I would advise changing your transmission when you change the engine. the 200r4s arent known for handling alot of power in stock form (even a mild 350 chevy's torque will eat it up in time). a 700r4 or a turbo 350 or turbo 400 trans wil handle the power alot better.
it is cheaper in the long run (and not much more in the short run). to change the transmission when you change the motor (not including cost of transmission) you're looking at a couple hundred more, as opposed to at least $1500 more a while down the road when your current trans bites the dust.
personally if you're looking for an easier installation, I'd go carb'ed on the 350 and put a turbo 350 or 700r4 behind it.

I dont remember if the 350s had the fuel pump in the tank or on the motor.
as for the alternator, it might swap across (depends on how the mounts are cast into it.) not all GM alternators from that time period had the same mounts. although if you buy a complete motor (long block) it might come with an alternator in which case you would not have to worry about how to bolt it up.

sven914
08-15-11, 08:29 PM
A Chevrolet 350 will swap in, but you should get (or at least have access to) a '90-92 Brougham with the 350. The '90 Brougham has the same chassis as your coupe and the engine mounts in the same place. To do the swap you need the Chevy engine mounts and if you want to make it fuel injected, you will need the computer.

The Chevrolet motor will not bolt to your transmission unless you get a BOP to Chevy bell housing adapter. If you get a '90's part's car, you can take the transmission and drive shaft to swap into your coupe. The TH 700 that comes with the Chevrolet will be stronger than the stock THM 200 bolted to the 4100.

If you want a cheaper and easier solution, you should look into getting an Oldsmobile 307 or 350. Both will bolt directly to your chassis and to your transmission. The 307 is carburetted, so you wouldn't have to deal a computer or electronics. The 350 can easily be converted to run with a carburettor.

jayoldschool
08-15-11, 08:35 PM
The 200-4R will bolt up to the Chevy. It has a dual bolt pattern.

drmenard
08-15-11, 08:58 PM
Hey Jay... I was waiting to hear that.. almost all of the 200 4r's have the dual bolt pattern... If it was me I would get a 90-92 parts car and I would have everything to do the swap...

jak89
08-15-11, 09:46 PM
So from what I've read so far if I get a 90's model chevy 350 either type of injection it will bolt up to my tranny, I will need the wiring harness and comp for that motor, chevy style mounts, and it should be a fairly easy swap?

cadillac kevin
08-15-11, 09:56 PM
correct. a 90-92 caddy brougham would be ideal if you can get one for about 800- 1000. it will have the engine , transmission, and all the random stuff you will need to hook it up (plus you get alot of usable non drivetrain parts for your car).

jak89
08-15-11, 10:28 PM
that would be ideal but I dont know if I could find one of those with a good motor and tranny for the right price. I just went to all the junk yards in my area today and I only found one caddy that was a rwd with anything I could use and the engine was no good. been searchin classifieds and all I can find for a reasonable price is motors with all acc., harness, and comp seems like my best bet atm. I just wanna know if it will work without going to extreme lenghs.


The only thing im not so sure about now is hooking up all the warning lights and ignition,I dont want one of those button start things. If I get the harness and ecu I should be able to put it in and make it run no prob. I dont have any experience in hooking up sensors or making my ignition switch work with a different motor,tranny,harness,and ecu. I just need to figure that out.

Would the plug from the ignition,and warning lights plug into a chevy ecu?

It would prolly help if I knew where the ecu is in this car so I can look at it.

jayoldschool
08-15-11, 11:20 PM
You are going to need to be good at wiring. Don't even consider this swap if you can't sort through a harness. You will need the FSM for the donor car, and your car.

jak89
08-16-11, 03:11 PM
What kind of electrical work would be needed to put a carbed 350 in? I've been thinkin about it and I think I would rather have a carbed motor instead.

outsider
08-16-11, 03:48 PM
depends if you want to do a computer controlled carb (like the ones on the later 87's 307's) or just a regular old manual carb i guess :)

jak89
08-16-11, 04:13 PM
Is a comp controlled carb better than a manual one? either way if I went carbed wouldent I need to get the o2 sensor,ignition,temp,oil press,alt,starter hooked up?

There insnt anyone who manufactures harnesses for these swaps?

Also I read somewhere that all 90's and later rwd caddys have the chevy drivetrain and will swap into my 85 coupe,meaning motor,tranny,and shaft. Wouldent a 4 door shaft be longer?

Man I feel so lost right now but Im gonna get all this figured out I have another newb question, Can u put a carb on any older 350?

outsider
08-16-11, 04:40 PM
I think you can...just need to change the intake manifold. I could be wrong, though.

csbuckn
08-16-11, 05:44 PM
Putting a carb on is easy, just run power to the dizzy and wire up the alternator. It would be neat to see a TPI 350 in an 85 though.

sven914
08-16-11, 06:28 PM
The Oldsmobile 307 usually has an electronic carburettor, but you can get a manual one for them. The Olds 350 can run with the 307 e-carb, but it will be heavily under powered.

A manual carburettor is just as reliable and fuel efficient as the electronic variety. The electronic ones were used because of the fuel metering requirements of OBD-1; the computer needed to have someway of adjusting the fuel flow. Your car no longer not needs to meet OBD-1 requirements, so the engine electronics and computer are disposable.

jak89
08-16-11, 06:34 PM
Thats what I really wanted to do but I cant find info on getting it done anywhere.

sven914
08-16-11, 10:54 PM
It's not that hard to do it yourself.

brougham
08-17-11, 01:34 AM
You can use a 93 Fleetwood too for the drivetrain. Same car as 91&92 but different body sitting on it. For that matter you can also use a Caprice or Roadmaster from the same years and they are cheaper and easier to find.
They only used feedback carburetors to meet emissions for the 307 years. If you're going carb route you'd be better off just getting a normal one anyway because the computer setup is designed for whatever engine and body it's in. Start mixing parts and you can can run into problems. Not to mention the extra wiring involved.

outsider
08-17-11, 07:52 AM
i really wanna swap an LT1from a 95 into my 87...haha that would be sick.

jak89
08-17-11, 04:44 PM
You can use a 93 Fleetwood too for the drivetrain. Same car as 91&92 but different body sitting on it. For that matter you can also use a Caprice or Roadmaster from the same years and they are cheaper and easier to find.
They only used feedback carburetors to meet emissions for the 307 years. If you're going carb route you'd be better off just getting a normal one anyway because the computer setup is designed for whatever engine and body it's in. Start mixing parts and you can can run into problems. Not to mention the extra wiring involved.

What do mean by I'd "be better getting a normal one anyway", It would be better to get a already carbed motor, right?

So far I've located a carbed 350 for a decent price but I'm gonna be a little more patient and see what else I can find.

jak89
08-17-11, 06:07 PM
Alright so I finally found some solid info for wiring with a manual carb I think. here it is

As far as wiring all you will need is the wiring from the altenator, oil pressure switch, coolant temp switch, ditributor,and the starter and battery wires. You can remove everything else.




now I just need to now what to hook these wires up to?

sven914
08-17-11, 07:32 PM
Alternator goes to the battery. The oil pressure switch is connected directly "STOP OIL PRESSURE" warning lamp. The coolant temp lamp is wired directly to the "COOLANT TEMP" lamp. The distributor would be connected to the battery, the spark plugs, and a manifold vacuum supply. The battery Positive wouldn't need to be moved and the starter will connect to the factory ignition switch.

The distributor is the only thing that your car has (from your list), which is computer controlled. Everything else is just plugged into what ever it controls and it maintains/monitors the system by itself. For the most part, you would be able to reuse the car's factory wring harness.

jak89
08-17-11, 08:13 PM
Why thank you, that clarified a lot. I found a 4 bolt main 1980 350 all it needs is a carb. its a four barrel motor. Can someone recommend a good series of carb to put on it?

jayoldschool
08-17-11, 08:29 PM
Edelbrock 1406. You would be better off getting an 87 or later roller cam small block, btw.

sven914
08-17-11, 09:08 PM
I would try to find a Rochester. A carburettor for a 350 or a 403 will work and a refurbished one isn't that expensive on eBay

cadillac kevin
08-17-11, 10:49 PM
sven, I think hes referring to the chevy 350, not the olds 350.

jak, get a 600 cfm rochester 4 barrel and you'll be ok. thats what the higher output 350s came with (high output is a relative term though)

sven914
08-17-11, 11:17 PM
But a carbed Chevy won't fit right. There isn't enough clearance between the frame and fuel pump.

cadillac kevin
08-17-11, 11:20 PM
isnt there a way around that?

sven914
08-18-11, 01:35 AM
Two options: take a sawzall to the fame or get an Oldsmobile engine.

csbuckn
08-18-11, 09:37 AM
The 4100 is Fuel injected, right? Just run a fuel regulator near the carb and you should be good. If you do need a pump, put an electric one on the frame close to the tank.

jak89
08-18-11, 06:31 PM
I was planning on using the stock fuel pump if its big enough? I am going to use a electric pump and a fpr.

I read somewhere a carb only needs around 9psi to work right is that true?

brougham
08-19-11, 01:46 AM
You're right about what you need for wiring. All you'd need to do is hook up the temperature and oil pressure sensors to the new engine and the alternator. For the distributor just use a stock vacuum one or common aftermarket one and follow the wiring diagram for it. It'll come down to 1 or 2 wires you'd have to tap into for it.
There have been a few people in the past who had carbed 305s and 350s on here. See if one of their old posts said what they did for the fuel pump. If a mechanical one won't work you can always use an electric one with a regulator. Still far easier to deal with that then get a fuel injected engine running in there.

jak89
08-23-11, 09:21 PM
I've found out that U have to get a aftermarket fuel pump to go from high psi injection to low psi carbeuration, There is no regulator that can make that much of a difference.

csbuckn
08-23-11, 10:26 PM
I just used a regulator to get mine from 12 to 5 psi.

jayoldschool
08-23-11, 10:44 PM
I've found out that U have to get a aftermarket fuel pump to go from high psi injection to low psi carbeuration, There is no regulator that can make that much of a difference.

That's for MPFI running at 60psi. Not TBI at 12psi.

jak89
08-23-11, 11:08 PM
I dont know but I found this info on putting a carbed 350 into a caddy but any clarifacation makes it that much better.

http://www.layitlow.com/forums/22-maintenance-repair/164875-350-swap-into-80-s-caddy.html?highlight=cadillac+engine+swap

CoupeDTS
08-24-11, 07:38 PM
Id like to see proof of getting the 15psi in tank pump regulated down to 5psi for a carburator. I tried a few different brands of regulators and after talking to tech guys on the phone at speed shops that sell these parts they confirmed what I had found by installing a bunch of these that they are for regulating pressure around what they are rated at not bringing pressure way down. Put a gauge on yours and see if you are really getting it down to 5psi. You put a 4-8psi regulator on a pump that makes 4-8psi to regulate it between 4-8psi. 15psi just maxes out the spring inside a smaller regulator and does nothing for regulating.

I mounted an electric pump where the original fuel filter mounts to the frame so that it is below the tank and pushes the fuel more than it pulls it. It will suck it right through the old pump so no need to buy a new sending unit for carbed caddys. You will need to plug your return line because gas will siphon back through that return line from the tank. The vent line you can leave open somewhere where water wont get in it.

Ive done this swap and helped out many who are also doing it. Ive worked out alot of kinks in the process. I drive my car on 500 mile trips a few times a year no problem, its very reliable and everything works as it should.

Let me know if theres anything else you need help on. That LAYITLOW.COM link is where I help out others with the swap.

jayoldschool
08-24-11, 09:35 PM
Your proof is in post 34. csbuckn has posted videos of his car running after the swap.

csbuckn
08-24-11, 11:31 PM
You will need to plug your return line because gas will siphon back through that return line from the tank.
I bought a fuel pressure regulator that had one input and two outputs, one output for the carb and one for the return line. I didnt measure the fuel pressure but it ran just fine at any speed. Anything beyond 7psi is returned to the tank and it has worked perfectly. I'd also put a filter on the vent so nothing gets in there.

jak89
08-25-11, 03:28 PM
I see how that will work are those type of regulators easy to find? Not to put any one down but, I have to say I like that method better.

csbuckn
08-25-11, 05:18 PM
This is the one I got. I put it on and didnt even adjust or measure it. They say it comes set at 5psi.
http://cgi.ebay.com/ebaymotors/Holley-Fuel-Pressure-Regulator-12-803-/330594826739?pt=Motors_Car_Truck_Parts_Accessories&hash=item4cf8fcb9f3#ht_1612wt_898

jak89
08-25-11, 09:02 PM
thanks for that link thats a nice regulator

I plan on using my rebuilt 2004r until it bites the dust. I'm wondering if I got the mounts out of a 90-92 brougham will I be able to bolt a chevy 350 in using existing holes with the 200r tranny?

I have no problem with welding the chevy mounts in welding is what i do but I would like to bolt the motor in if possible.

CoupeDTS
08-26-11, 11:58 PM
I have one of those chrome regulators brand new if anyone wants to buy one still in the packaging. Same kind I used on mine. Dont use it with the stock pump tho.

The return line regulators are a whole different kind of regulator. I never did test one of those out but in theory it should work. I had so much bad luck with other regulators I was done fooling with it and bought a $35 fuel pump and was done with it. Also I was trying to keep the engine bay as clean as possible and didnt want more gas lines in it. If it works thats awesome thats just another option people have when doing the swap :)