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Any difference between 89 700r4 in a V6 and 87 in a trans am

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Old Oct 14, 2024 | 09:54 PM
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drsnac's Avatar
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Car: 1987 Trans Am
Engine: 305 TPI
Transmission: 700R4
Any difference between 89 700r4 in a V6 and 87 in a trans am

Just want to make sure the bell housing is the same before I drop the trans from my 2.8 and start beefing it up for the 350 Im going to build
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Old Oct 14, 2024 | 10:23 PM
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From: Franklin, KY near Beech Bend Raceway, Corvette Plant and Museum.
Car: 1992 Pontiac Firebird
Engine: 5.0L L03 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

The 2.8/3.1 V6 700R4 trans has the GM Corporate 60 degree V6 bolt pattern bellhousing and the other has the Chevy 4.3 90 degree V6 & SBC/BBC 90 degree V8 bolt pattern bellhousing.
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Old Oct 15, 2024 | 09:18 AM
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Car: 1987 Trans Am
Engine: 305 TPI
Transmission: 700R4
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

Originally Posted by Airwolfe
The 2.8/3.1 V6 700R4 trans has the GM Corporate 60 degree V6 bolt pattern bellhousing and the other has the Chevy 4.3 90 degree V6 & SBC/BBC 90 degree V8 bolt pattern bellhousing.
So does that mean it wont work with a 350?
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Old Oct 15, 2024 | 09:29 AM
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72buickgs's Avatar
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From: Windsor, On
Car: 1984 Trans AM
Engine: 305
Transmission: 700-4r
Axle/Gears: 3.23
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

Originally Posted by drsnac
So does that mean it wont work with a 350?
If it will not match up bolt-wise, I would imagine that an adapter is available.
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Old Oct 15, 2024 | 01:17 PM
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Airwolfe's Avatar
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From: Franklin, KY near Beech Bend Raceway, Corvette Plant and Museum.
Car: 1992 Pontiac Firebird
Engine: 5.0L L03 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

Yes it means it won't work with a Chevy 350. A Chevy 350 is a 90 degree V8. You will need a 700R4 for a SBC that has a tail housing to mount the torque arm used in a 3rd gen Camaro or Firebird. I guess the tail housing off your 2.8 V6 trans would work. It can't be a 700R4 from a Corvette though as I think the case is different where the tail housing mounts to it. Also don't need the TA mount tail housing if using an aftermarket crossmember that has a TA mount and a aftermarket TA setup that doesn't mount to the transmission tail housing.

Rebuildable cores for a 700R4 transmissions are a dime a dozen. You wouldn't adapt a 60 degree V6 transmission to a 90 degree V8 application when GM made millions of them to fit a 90 degree V8.

Last edited by Airwolfe; Oct 15, 2024 at 02:35 PM. Reason: Grammar and to make better sense.
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Old Oct 15, 2024 | 01:27 PM
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Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

The 6-cyl transmission is inferior to a V8 one in several ways (valve body calibration, servo, clutch packs, etc.) as well as not bolting up.

Get a V8 one to use for your core and throw the 6-cyl trash in the trash. Or, put it on craigslist or something, there's sure to be somebody who needs one, maybe not right away, but sooner or later.
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Old Oct 15, 2024 | 07:36 PM
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

The V6 Torque-Converter will also not Bolt to the Flex-Plate for a Gen-I SBC.
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Old Oct 16, 2024 | 09:15 PM
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From: honolulu
Car: '86MCSS
Engine: 396 .030"
Transmission: M20
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

These are pics of manual transmission bellhousings but you can clearly see the difference in the bolt pattern between a 60* V6 and a 90* V6/SBC...
https://www.thirdgen.org/forums/atta...gsv8vs6cyl.jpg
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Old Oct 16, 2024 | 11:04 PM
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From: Franklin, KY near Beech Bend Raceway, Corvette Plant and Museum.
Car: 1992 Pontiac Firebird
Engine: 5.0L L03 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: Any difference between 89 700r4 in a V6 and 87 in a trans am

Where are you located? @Edsiroc just posted he has good working 700-R4 up for grabs for about $300.00 if anyone is interested.

Southern California Area - Any interest in a good working 700r4?
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