I am looking to do a engine swap with a 4.9 Liter Cadillac carburated engine. I have alot of questions.

Do you have to do anything with the computer in the car?

Do they sell mounts for it or do i have to make my own?

Does the stock 4cyl tranny work with a v8?

Do you have to change anything with the wiring hardness?

What kinda springs do i need to use for the back end?

Are there any parts needed to do the hole thing?

I will have alot more questions as i do more research on it.

Thanks

I would suggest doing a search and I am sure someone else will mention it. Also the website fieroaddiction.com is great for info, he changed his website to an online store not to long ago so you have to click on the fiero addiction information site on the right upper corner to get to his info site. He also sells a mount that you can use in conjunction with stock tranny mounts and one of the stock caddy mounts. I am in the middle of doing a 4.9 myself and have found that putting it together is the easy part. I am starting wireing at the moment and that is a pain. The carb engine setup still reqiures some wiring but not as much. From what I have heard you are robbing power from yourself to go carbed for the sake of convenience but to each his own.

You should not need anything special suspension wise, apart from a well tuned ride to handle the power. The 4.9 if I remember right actually weighs noticeably less than the 2.8. The stock manual transmissions available for the fiero will bolt to the 4.9 just fine. You will need to get a flywheel from LSC or get a neutral balance 2.8 one redrilled. As far as the 4spd goes you are going to want an 85 (maybe 86?) or later as the housing was reinforced otherwise you are going to tear that thing apart with the 300 ft lbs of torque. Also you either need a mini starter from a caddy allante (you can get them from ebay and other places for $50) or you have to cut/grind a space out of the bellhousing to fit the original starter from the caddy.

As far as special parts go a different throttle cable is usefull (87? 88? not sure) late model 4cylinder throttle cables from a fiero work. Also you need a three pin temp sensor and a few odds and ends to delete the power steering from the engine and allow you to run the belt.

The caddy air conditioning compressor will work, as will the alternator from the 4.9.

Good luck on your project and keep us updated. Hopefully yours will bear fruit sooner than mine....going on a more than a year now and still not done.

Dizzixx put it very well. My comment is to keep the fuel injection, don't use the carb. The car will just run better with the PFI system. The wiring is not that hard. You can get all the answers here on the forum.

Jack

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If you can not run with the big dogs, stay on the porch!

You will get terrible mileage and decreased drivability with a carburetor. Its also more expensive to strip the EFI stuff off and put a new manifold with a 4bbl carb on the engine.
If you are scared or intimidated by wiring, Fuel Injection Technology can supply a complete plug and play harness and I believe dansflyer can make one for you too.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
87GT - 3.4L Turbocharged engine, modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I should of been more specific cause i have a 87 fiero 4cyl auto. Will that all be the same?

Does the computer in the car need to be configured or reprogrammed for a v8 fuel injected?

[This message has been edited by Fieroboy87 (edited 01-27-2009).]

http://members.fortunecity.com/bubbajoexx/ explains how to make an adapter plate for the 4.9 intake as well as telling you how to modify to distributor. I have an 87 2.5 with a 5 spd Isuzu that I am doing this swap in. I didn't want to mess with the EFI and swapping ECMs, making a harness, etc, plus I do not have the money to have someone make a harness, etc. I plan on keeping the EFI stuff and may switch it back later once finances improve, but for now a carbed one is within the budget. I also know that a well tuned carbed motor can get very good mileage. I had a 74 Cougar with a 351C/2bbl stock, that as long as it was tuned up like it was supposed to be, it got 25MPG consectively. Just be cause a carb is old technology, does not mean it is bad technology. One thing you may have to think about though is if you have smog testing, etc. That may determine if you can go carbed or EFI. Just my .02 worth. Good luck on your swap, post pics, and I will post pics of mine on my build thread......once it warms up some and quits snowing, lol. Keep us posted

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

quote Originally posted by Fieroboy87: I should of been more specific cause i have a 87 fiero 4cyl auto. Will that all be the same? Does the computer in the car need to be configured or reprogrammed for a v8 fuel injected?

If you want to stay auto, I HIGHLY recommend using the 4T60E transmission that came with the 4.9. 1900 RPM @ 70 mph. An overdrive is a very good thing. Plus, it's already built to withstand the power. You won't use the Fiero's ECM any longer....you will use the PCM from the Cadillac to control the engine and the transmission.

I've had this swap in my 88 coupe for 3 years now and love it. 20 mpg around town and tons of low end torque.

quote Originally posted by Fieroboy87: Does the computer in the car need to be configured or reprogrammed for a v8 fuel injected?

If you swap in a 4.9 V8 you will not be using the computer that came with the Fiero...you will be using the computer that came with the 4.9 engine. It will either have to be re-programmed to work in the Fiero, or at least have a module to eliminate the VATS so it will start. If you go with a carburetor, you won't need a computer at all.

So if I use the trant that comes with the engine does that mean i have to get new axles or can i use the stock ones. If i stay with the stock 4cyl tranny will the engine work with it or not.

quote Originally posted by Fieroboy87: So if I use the trant that comes with the engine does that mean i have to get new axles or can i use the stock ones. If i stay with the stock 4cyl tranny will the engine work with it or not.

If you go with the transmission that comes with the 4.9 you will need new axles. I forget which ones, but they are commonly available as used on other cars.

The stock Fiero transmissions use stock axles...

Does the stock tranny work with the 4.9 liter engine?

quote Originally posted by Fieroboy87: Does the stock tranny work with the 4.9 liter engine?

Define "work"?

The stock 4 cyl transmission was designed for an engine that makes half the horsepower and about a third the torque of the 4.9. The stock transmission will mate to the 4.9 and it will propel the car forward and backwards. But if you mate the two it's not a question of if but WHEN will it break.

If you baby it, (no power shifting, no sidestepping the clutch, etc) it might last indefinitely, but in the back of your mind you have to be aware that it's a delicate system.

If you use the transmission that came with the 4.9, (or the 6 speed) it's going to be rated to take the full power of the engine, (with margin on top of that).

When I first built my 4.9 car I went with the transmission that came with the engine for reliability. But I HATE autos, and when the 6 speed option became available, I pulled the auto, (and sold it) and installed the 6 speed. I love it.

[This message has been edited by jscott1 (edited 01-28-2009).]

All of my reading on the subject says that yes, you can use the Fiero auto, but, the caddi auto is a lot stronger tranny. Not sure on the axle question, but there are numerous links on the forum and in the archives that detail this swap, including using the tranny. I am going carbed on mine because 1) I want to do away with all computer control in the car, 2) I am running a manual and don't want to have to mess with getting a chip burnt, programmed, etc, 3) I can work on a carbed engine a lot easier than I can on FI, 4) I have everything I need to make the engine carbed, 5) I am doind a custom dash treatment and want to use aftermarket gauges, etc that I had already purchased for a different project, 6) seams to me that a carbed setup would be easier to complete on a budget than an FI swap.

These are just my reasons. http://www.fieroaddiction.com/store2/ makes 4.9 mounts that use the stock locations on the cradle, as well as programming of the ECM, which if you go with the caddi tranny you will have to have. He also has a link on his site that explains the swap. Also, the link I sent in an earlier post has a wealth of info on a lot of different swaps available for the Fiero. I would search the forums/archives here, do a google search, read up on the different pros and cons, then dive in and have fun, and if you run into trouble during your swap, there are many knowledgeable people on the forum that can get you back on track, Good luck, William

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

Here is a post I did on another thread about the 4.9 swap. It has a couple of other links in it as well.

Just my .02. I am doing a 4.9 carbed in my 87. I know that the prom and all can be programmed, etc, but I like the idea of 1 hot wire to a distributor and it will crank and fire. Bubba Joe has a great writeup on how to do the swap and mod to make it carbed. Nice thing about the 4.9, it bolts up to the fiero tranny without an adapter plate, it is a solid engine, and fiero addiction has the mounts to make it extreamly easy to do the swap. Here are the links for mounts and how-to
http://www.fieroaddiction.c...02878373d19b27ed7372
http://members.fortunecity.com/bubbajoexx/id18.htm
It would be, in my opinion, an easier, somewhat cheaper swap, especially for the 84 with it's one-off wiring that everyone talks about. It would also give you that nice V8 sound
Here is another link you might look at. http://www.angelfire.com/fl.../fierolinks_009.html
Just my .02 worth. There are about as many swaps out there as there are engines, and with some inginuity and mechanical know how, I would say anything is possible. Good luck on which ever swap you decide on.

[This message has been edited by thumper_64735 (edited 01-28-2009).]

quote Originally posted by Fieroboy87: Does the stock tranny work with the 4.9 liter engine?

yes they do. the manuals need to have a notch in the bell housing to clear the starter unless you get one of the smaller after market starters.

quote Originally posted by Kento: yes they do. the manuals need to have a notch in the bell housing to clear the starter unless you get one of the smaller after market starters.

...or the (smaller) Allante starter...

quote Originally posted by Dennis LaGrua: You will get terrible mileage and decreased drivability with a carburetor. Its also more expensive to strip the EFI stuff off and put a new manifold with a 4bbl carb on the engine. If you are scared or intimidated by wiring, Fuel Injection Technology can supply a complete plug and play harness and I believe dansflyer can make one for you too.

Here we go again. Putting a 2 barrel Holley on the 4.9 is just plain easy as mods go. You have to create an adapter plate and put an older 4.5 Distributor on it, but it will deliver good gas mileage, be really simple to keep in tune and breath well for the engine. It will be a 500 cfm 2 barrel you want.

One thing I don't like is old electronic parts. Great if they work, but not so great if they need to be serviced. Same with old injectors. Bottom line is that if you want the simplicity of the carb it will work just fine. If you prefer the OEM fuely equipment it will likely work well also. It just depends on what you want. As for driveability, the 2 barrel carb is a dream to operate.

Arn

As for axles.....if you use the 4T60E, you will buy a set of 1993 Pontiac TransPort or Oldsmobile Silhouette minivan axles. You will remove the outer ends (held on by snap rings) and replace them with the outer ends from a Fiero with a STANDARD transmission. They will snap right back on. Repack the boots full of grease, replace the boot clamps, and you're good to go. They will fit and work just like they belong there. I've used this combo for about 4000 miles on my swap with no issues.

Honestly, I wouldn't even consider using the TH125 with a 4.9. They will bolt together, but you will hate it the first time you get the car over 50 mph and see how high the RPM is. The added overdrive makes everything operate much better....after all, the trans was engineered to work with the 4.9 from the get go.

Good luck in whatever you decide....we're here to help.

Thanks too all keep posting all the information i get i appreciate. Im looking for the engine and tranny but i might wait alittle and see what i can find. I will keep everybody posted on what i am going to do.

thanks again

[This message has been edited by Fieroboy87 (edited 01-28-2009).]

If you were closer, I know where there is another 4.9 with tranny out of a deville, can't remeber year right now, for 150.00, maybe an extra 20 or so for the harness and puter, and that is a complete setup. IF anyone is interested, I could go pull it and ship it for actual shipping plus a little for crating it up, plus some money for my time. Just a thought for you.

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

wow i wish i as closer that cheap for engine and tranny and even maybe wiring harness. I hope i can find a deal like that

quote Originally posted by Frizlefrak: Honestly, I wouldn't even consider using the TH125 with a 4.9. They will bolt together, but you will hate it the first time you get the car over 50 mph and see how high the RPM is.

And from what I understand it will suck gas like nobody's business.

I'm not too sure that a properly tuned 4.9 carbed would do too bad. I had a 351C in a 74 cougar that was bone stock that got 24MPG average. I have a 305 in an 84 chevy truck that gets around 18-20 MPG. I feel that a properly tuned 4.9 with the correct cfm carb would be fairly fuel efficient. Once I get my swap done and running I'll let youknow. I know my 5 spd gets better mileage than the auto I had at first did. If I was installing the 4.9 in an auto, I would install the auto tranny out of the caddi as well. Just my .02 worth
William

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

quote Originally posted by thumper_64735: I'm not too sure that a properly tuned 4.9 carbed would do too bad. William

I was referring to the 3 speed transmission causing the 4.9 to suck gas.

The fiero 3 speed auto tranmission was designed back in the 80s for the 55 mpg. You get the 4.9 reving to some number rolling down the highway at 80 mph with the Fiero 3 speed auto tranny you are going to be miserable.

sorry, misunderstood. I agree with you there. My 85 auto with a 4 banger got about the same if not worse milage than the cougar did. I'll never have a stock auto fiero as a daily driver if I can help it.

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

quote Originally posted by thumper_64735: I'll never have a stock auto fiero as a daily driver if I can help it.

Agreed. I had a duke auto and it never got better than 26 mpg. For that miserable amount of power I expect better mileage. I get the same if not better mileage from my 2.8/5 speed.

What type of mileage is everyone getting out of the 4.9/4spd auto swaps? Just curious, and not meaning to hyjack the thread.

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Hmmmmmmmmm.......now if I can just talk the Army out of an engine, I bet I can get it to fit hehehehehehe >

quote Originally posted by thumper_64735: What type of mileage is everyone getting out of the 4.9/4spd auto swaps? Just curious, and not meaning to hyjack the thread.

I'm getting between 17-19 around town. If I do mixed city and freeway, around 21 mpg. I've never taken it on a trip, but I would suspect mid 20's. And I'm leadfooted with it. It's just too much fun to be gentle with.

At 70 mph in overdrive, it's turning over about 1900 RPM.

Out on the open road you should get around 30 MPG. I run a 6 speed behind mine, turn a little over 2000 RPMs at 70 MPH and get 30 MPG out of it.

Jack