What is the difference between the 85-88 TB and 89-92 TB?

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Dave
86 Vette Conv.

 

They are all the same.

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Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.

 

If they're the same then why do they have different part numbers yet cost the same? I think there is a difference due to the MAF/SD difference.

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'91 GTA with TPI 350 & T-Tops. Just a few mods, if you want to find out just line up next to me at a stoplight!

Added bonus:
Wife's car is a '00 Grand Prix GTP!

[This message has been edited by blacksunshine'91 (edited March 19, 2001).]

 

THEY ARE NOT THE SAME!!! The 85-88 T.B.'s use a different THROTTLE CABLE attachment, kind of like a CARB. The 89-92 use a "ROTATING CAM" style actuation, similar to a CROSS-BOW cam. The cable rides in a grooved channel in the 89-92 T.B. with a special end that rests secured into the cam perpendicular to cables arc of travel. If you look at the mounting face of both the 85-88 and the 89-92, you will see a distinct difference. The 89-92 can be substituted for an 85-88 as long as you also use the appropiate year THROTTLE CABLE with it. HTH's

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88 Monte SS 355 TPI/LT-4 HOT CAM/AFR Hydra-rev/ T-56 6-Speed/1-3/4" full length headers/3" X-PIPE assembly/ 8.5" G-80 rear with 3.73 gears.
community.webshots.com/user/ssynergy
www.y-t-g.com/88monte

 

Thank-You!

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Dave
86 Vette Conv.

 

Another major difference is the Idle Air Control inlets between the 85-88 and 89-92.

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1989 IROC-Z 5.7L

 

The IAC setup was changed in 90, not 89.

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89 GTA G92
305 TPI WC 5spd w/3.45
Accel Cap & 8mm Taylor's
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch TB Bypass - Steel Rad
Cat back 3" Exhaust w/Terminator Muff.
HiGh FlOw Dynomax Cat
Spohn LCA's - KYB GR-2's
Moroso Crank Bolt and roller pilot bearing.
Autometer Vac+Oil Temp

 

It was 89. The 89 TB is the same as the 90-92. The 89 TB does not have the IAC passage in it like the 85-88's do.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

LOL, I thought he meant the size, 48mm!!

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Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.

 

What controls the idle air without an IAC on the 89-92 TB

 

No, 89-92 has an IAC, but the passages are different than 85-88.