If I understand it correctly, the manifold bases differred from 85-86 and 87-92 with the later years having the center manifold bolt angled for the 87-later heads.

The runners were 85-88 (w/ cold start injector hole) and 89-92 (w/o cold start injector hole).

The plenums were 85-88 (w/ cold start passage), 89 (w/o cold start passage), and 90-92 (w/o cold start passage & w/ MAP boss).

What about the throttle bodies? From what I can find there was a difference between the 85-88 and the 89-92 TB's but I don't know what those differences were.

Am I correct on my descriptions? Any other info would be appreciated. Thanks.

[This message has been edited by Dana92RS (edited October 26, 2000).]

 

You're correct on the plenum/runners/base. The TB difference is the way the IAC passage routes, and the way the throttle cable connects.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
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