What is the difference between throttle bodies from an 88 and an 89 5.7 tpi?

I see that the part numbers for aftermarket TB's are different for those two years. I have an 89 IROC but I want to buy a TB from an 88 Formula. Will it work?

 

an 88 can work on a 89 but a 89 cannot work on a 88.

Its a IAC passage on the 88, the 89 and up do not have this passage

 

That won't affect the way it idles will it?

 

Block off the passages with a plate and it'll be fine. Just make sure it seals good.....vacuum leaks are bad!

 

there is no passage on the front of the plenum on the 89, so you have nothing to worry about!.

TheGreatJ...the passage is on the backside of the TB, no need for a plate cause it sits flush up againt the area of the plenum where the hole is already blocked.

 

The throttle cable is different too. The way the cable connects is different on 85-88 and 89-92 throttle bodies.

 

Thanks for all the info. Next question, does anyone have a good pic of the throttle linkage from an 88? The pic I have does not show the linkage very well.