Oldsmobile 425 into '87 Firebird
Thread Starter
Joined: Jun 2002
Posts: 202
Likes: 4
From: Altus, Oklahoma
Car: Dad's 87 Bird (Org Owner)
Engine: Vortec 350 Crate Motor
Transmission: TH350
Axle/Gears: 3.42 Posi
Oldsmobile 425 into '87 Firebird
I have the opportunity to do this.
What are your thoughts of doing this vs a stock Vortec 350?
What are your thoughts of doing this vs a stock Vortec 350?
Supreme Member
Joined: Oct 2001
Posts: 8,113
Likes: 6
From: NWOhioToledoArea
Car: 86-FireBird
Engine: -MPFI
Transmission: T5
Axle/Gears: 3:42
Re: Oldsmobile 425 into '87 Firebird
BOP GMC Be Original, Think Out side the Bowtie... besides that there is a tenancy with the more odd the build, the less likely they are heard from again...
Last one I followed was a Buick 455 into a 3rd gen. Never heard from again once done.
my theory is non chevy engines turn 3rd gens into a time machine...
I just happen to have a BB Buick stage 1 430, race prep TH350 just sitting on a stand doing nothing.
But there isn't enough steel in these things for me to attempt time travel....
Last one I followed was a Buick 455 into a 3rd gen. Never heard from again once done.
my theory is non chevy engines turn 3rd gens into a time machine...
I just happen to have a BB Buick stage 1 430, race prep TH350 just sitting on a stand doing nothing.
But there isn't enough steel in these things for me to attempt time travel....
Joined: Jul 2000
Posts: 6,522
Likes: 92
From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R
Re: Oldsmobile 425 into '87 Firebird
How much technology do you think is in 30 years and billions of dollars in combustion and airflow research? The 425 will get eaten alive and the L31 will pull several more miles per gallon afterward. Spending more to get less? Having the car be worth less when you're done? Skip the old.
Thread Starter
Joined: Jun 2002
Posts: 202
Likes: 4
From: Altus, Oklahoma
Car: Dad's 87 Bird (Org Owner)
Engine: Vortec 350 Crate Motor
Transmission: TH350
Axle/Gears: 3.42 Posi
Re: Oldsmobile 425 into '87 Firebird
That's what I was leaning towards. I installed a new crate L31 in my car about a year and a half ago and it runs great.
I am getting a complete carb-to-pan Olds 425 for cheap. I'll just stick it in the garage for another project.
Thanks 3rd Gen.
I am getting a complete carb-to-pan Olds 425 for cheap. I'll just stick it in the garage for another project.
Thanks 3rd Gen.
Joined: Oct 2001
Posts: 12,221
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From: Il
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Oldsmobile 425 into '87 Firebird
I saw a buick 455 in a 3rdgen at a local show, looked like a factory install with AC and all. I think most guys that do end up doing and finishing something like this don't get on the net much if ever.
Odd but In June of 2000, Hot Rod mag has a buick 455 in a 3rdgen and it looks a very nice factory install.
Odd but In June of 2000, Hot Rod mag has a buick 455 in a 3rdgen and it looks a very nice factory install.
Last edited by TTOP350; Nov 5, 2016 at 11:17 AM.
Joined: Sep 2005
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Re: Oldsmobile 425 into '87 Firebird
I think most guys that do end up doing and finishing something like this ...
Reserve the Olds motor for ... an Olds.
There's plenty of those out there (well, maybe not "plenty", but "some" anyway...) that can make better use of it than this.Do a couple of simpler swaps first to gain some experience before tackling something exotic. Just like, I wouldn't want to be the first patient an aspiring brain surgeon operated on, before he went to medical school. At least, assuming I had a brain to begin with. Learn, gain experience, see how things can go wrong and what solutions work and what don't, acquire tools, parts, materials, contacts, & skills; THEN tackle the exotic.
Joined: Mar 2014
Posts: 4,553
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From: South Ms
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: Oldsmobile 425 into '87 Firebird
How much technology do you think is in 30 years and billions of dollars in combustion and airflow research? The 425 will get eaten alive and the L31 will pull several more miles per gallon afterward. Spending more to get less? Having the car be worth less when you're done? Skip the old.
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Joined: Jul 2000
Posts: 6,522
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From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R











quoted for truth.