305 to 350 swap DONE!!!
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, 305 to 350 swap DONE!!! in Past Cadillac Vehicle Discussion; I am one happy guy tonight. A few hours ago I got done swapping an 87 L98 5.7 Iroc motor ...
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    Destroyer's Avatar
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    305 to 350 swap DONE!!!

    I am one happy guy tonight. A few hours ago I got done swapping an 87 L98 5.7 Iroc motor into my 91 FWB in place of the factory 305. The engine swap was smooth but still took me the better part of 3 days. The motor runs great. I was concerned because its been sitting around for over 2 years but it started on the first crank. I took a big chance here cause I bought the Fleetwood with a bad motor, it ran ok but smoked real bad. The 350 Iroc motor I got from a buddy of mine which had a rear end accident with his Iroc 6k miles after he had a rebuilt done to his motor for a cost of $2800. Anyway the motor didn't start since then. He moved back to NJ and sold me the motor for $200. Till now I had no use for it but I was nervous to use it because I didn't know if it would run. It all worked: mint condition 91 FWB with bad motor $1200, newly rebuilt Iroc 350: $200, misc parts like starter, water pump, etc.....$150. Got a real nice running/looking Fleetwood for a total cost of $1550.

    Got a question for some of you that may have done a swap like this. I used the stock TBI setup for the Fleetwood. I was told that I would have to use a TBI setup and chip from a vechicle equipped with a 350 TBI and that the 305 setup I used would result in a real lean running vechicle. My question is how do I know if its running lean? It starts right up and seems to run great, so why would I need the larger TBI and chip? If the car will run better I'll definately do it but will it?

    I need to take some good pics of the car but here are some pics of the swap over the last 3 days.

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    Re: 305 to 350 swap DONE!!!

    That is one beautiful automobile! The new engine looks good too. I wish I could save myself some money by doing it myself, but don't have the tools or know how. I know a mechanic who said he would pull my engine, transfer parts onto a new block and drop it back in there for about $300 plus parts. But I need to find a reman 403 without having to sleep in my car, know what I mean. I hope I can do it all for $1500 or less. Then I will be as happy as you are now. If I could get a complete crate 403, I would put a few extra hundred into it but the crates I've gotten prices for have been in excess of $2500. Any suggestions anyone?

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    Re: 305 to 350 swap DONE!!!

    A couple of weeks ago I sold my 87 Fleetwood with the 307. It ran fine but was really lacking in the power department. I contemplated putting my 350 Chevy in it or just getting a 403 Olds, even looked around for a 455 Olds or 472/500 Caddy motor but decided it just wasn't going to be worth it dollar for dollar. My 87 also needed a new top and paint in the near future so I decided to sell it. I'm an investor, I dont just throw money away so I decided to sell it before I dumped money into it that I'd never see again.

    Honestly, your best bet would be to find a donor car with a good running motor. If you want a 403 you have a few options as to what kind of donor car to get. A crate 403 is priced pretty high (I looked into it awhile ago). I've built Big block Olds motors but dont know much about parts interchangeability between small block 307's and 403's. I believe there are only few things you can swap over. Good luck with your car bro.

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    Re: 305 to 350 swap DONE!!!

    AHHHH

    another project that puts my stuff to shame!

    one day....

    If that was me, I would have modified the 350 before putting it in... or was it already moded?

    looks great though! both the car and engine... you have a nice combo there

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by Destroyer
    I am on

    Got a question for some of you that may have done a swap like this. I used the stock TBI setup for the Fleetwood. I was told that I would have to use a TBI setup and chip from a vechicle equipped with a 350 TBI and that the 305 setup I used would result in a real lean running vechicle. My question is how do I know if its running lean? It starts right up and seems to run great, so why would I need the larger TBI and chip? If the car will run better I'll definately do it but will it?

    I need to take some good pics of the car but here are some pics of the swap over the last 3 days.
    i would recommend changing the TBI to ensure your engine last and performs to it's fullest.

    The only way i know of to know if an engine is running lean is by checking the spark plugs.

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    Re: 305 to 350 swap DONE!!!

    If it were me, it would have an extra 150ci, but that's just me. Can't fault you for using an engine you already had and it will sure move around better than with that 305.

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    Re: 305 to 350 swap DONE!!!

    Your Brougham looks the same as mine. It's the same colour but mine is a Brougham D'Elegance and is a 5.7Litre one.
    They work good with the 350. I don't know if I would have used anything bigger. Especially if you're going to drive it a lot and since you already had the engine.

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by Destroyer
    A couple of weeks ago I sold my 87 Fleetwood with the 307. It ran fine but was really lacking in the power department. I contemplated putting my 350 Chevy in it or just getting a 403 Olds, even looked around for a 455 Olds or 472/500 Caddy motor but decided it just wasn't going to be worth it dollar for dollar. My 87 also needed a new top and paint in the near future so I decided to sell it. I'm an investor, I dont just throw money away so I decided to sell it before I dumped money into it that I'd never see again.

    Honestly, your best bet would be to find a donor car with a good running motor. If you want a 403 you have a few options as to what kind of donor car to get. A crate 403 is priced pretty high (I looked into it awhile ago). I've built Big block Olds motors but dont know much about parts interchangeability between small block 307's and 403's. I believe there are only few things you can swap over. Good luck with your car bro.
    Yeah, Destroyer, I too have contemplated selling it and looking for another. I am dying for a 94-96 with the LT1. But I love my Brougham. I already sank $950 in it for a tranny rebuild and would have to sell it for enough to at least break even. I would need to get a least $1950 to break even. On one hand it would be cheaper to sell it and get another, and on the other hand I would lose what I already have in it. Besides the rebuilt tranny, it has brand new Uniroyals, new valve cover gaskets and a real nice Sony cd player. And I didn't even include the stereo in the $1950. Overall the car is in good shape, but has no power, and smokes, sometimes worse than others.

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    Re: 305 to 350 swap DONE!!!

    Job well done Awsome deal! You got yourself a nice ass ride for such little money. Hey, you might as well keep the TBI setup, can't beat that for fuel economy and cold startups and such. And there are plenty of aftermarket parts to hop up the TBI if you wanted to.

    The only thing, that orange paint has gotta go, too chevy looking, IMHO...

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    Re: 305 to 350 swap DONE!!!

    Nice job! Not that I know for sure but my guess would be that the TBI unit from the 350 is no different than yours (maybe the injectors are different). You can check this through the dealer if you want. Also, you can check the O2 sensor feedback to see how the engine is running. Check your cross-counts. Most likely, if the engine "feels" good, and you're not getting a check engine light, the fuel system is keeping up with the engine's needs. The LT1 would've been better but it would've been a lot more work and a lot more expensive. Bottom line, you have a real clean car that runs even better than it did originally. What more could you ask for?

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by Katshot
    Nice job! Not that I know for sure but my guess would be that the TBI unit from the 350 is no different than yours (maybe the injectors are different). You can check this through the dealer if you want. Also, you can check the O2 sensor feedback to see how the engine is running. Check your cross-counts. Most likely, if the engine "feels" good, and you're not getting a check engine light, the fuel system is keeping up with the engine's needs. The LT1 would've been better but it would've been a lot more work and a lot more expensive. Bottom line, you have a real clean car that runs even better than it did originally. What more could you ask for?
    I think you are right as far as the TBI is concerned. I went to the auto parts store to get 91 Caddy 350 injectors but first asked if they were the same as the ones for the 305, they had the same part number so I didn't bother getting them. Car runs great so till I start modding I wont mess with anything else.

    LT1's are great motors, I've owned 3 cars with LT1's. They are a bit temperamental and I've gone through my fair share of optisparks though. LT1 wasn't even an option here. Like you said, costwise and workwise it would have been a lot more of a pain. Besides would it really be worth all that for an extra 50 horses? I'm getting a set of Vortec heads, headers, dual exhaust, converter and 3.73 gears. I'm undecided as far as if I will stick with TBI or switch to carb at that point, guess I have to see whats available for TBI injection in the aftermarket. I think I can get it substantially faster than a stock LT1 with not a whole lot of work.

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by evilrussian
    Job well done Awsome deal! You got yourself a nice ass ride for such little money. Hey, you might as well keep the TBI setup, can't beat that for fuel economy and cold startups and such. And there are plenty of aftermarket parts to hop up the TBI if you wanted to.

    The only thing, that orange paint has gotta go, too chevy looking, IMHO...
    Heh, Once I painted I thought it was a little too bright but didn't feel like making another trip to the parts store. Oh well.

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by Scottie in Alabama
    Yeah, Destroyer, I too have contemplated selling it and looking for another. I am dying for a 94-96 with the LT1. But I love my Brougham. I already sank $950 in it for a tranny rebuild and would have to sell it for enough to at least break even. I would need to get a least $1950 to break even. On one hand it would be cheaper to sell it and get another, and on the other hand I would lose what I already have in it. Besides the rebuilt tranny, it has brand new Uniroyals, new valve cover gaskets and a real nice Sony cd player. And I didn't even include the stereo in the $1950. Overall the car is in good shape, but has no power, and smokes, sometimes worse than others.
    Actually I didnt mean to sell your car but instead buy another car with a 403 (for cheap) and swap the motor over to your car.

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    Re: 305 to 350 swap DONE!!!

    Quote Originally Posted by brougham
    Your Brougham looks the same as mine. It's the same colour but mine is a Brougham D'Elegance and is a 5.7Litre one.
    They work good with the 350. I don't know if I would have used anything bigger. Especially if you're going to drive it a lot and since you already had the engine.
    Cool. I love the color of this one. My 87 was white with blue top and I hated that combo. I was really surprised at how much different the 91 drove as opposed to the 87 plus how much they updated the Fleetwood since 87. Any ideas about wheels/tire combo's on this car? I'm looking to get a wheel/rim combo 17"-20" but dont know what will fit.

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    Re: 305 to 350 swap DONE!!!

    That's a nice workshop you got going on over there. Did you rent that hoist and other speciality tools or is it all yours. Do you tackle projects like that often?

    Damn, I gotta move to a 2 car carage house. My 1 car garage just isn't big enough anymore My wife is naggin cause all the junk seems like it's breeding and starting to take over the office

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