i got a y8 manifold it was an auto one but i drilled it for the iacv and i have a 88-91 si throttle body but it wont fit on the y8 manifold.

 

The only throttle bodies that will fit the y8 manifold would be the 1992- 2000 year D-series,B series, and H- series throttle bodies... The throttles bodies that were made before 1992 will not fit because Honda changed the bolt pattern.
I had the same trouble too
Does the Y8 manifold actually bolt on the D16A6??

 

There is 2 different kinds of IACV. Some have mounting holes further apart then the other. The furthest one is the rare one. The close one (more then likely what you have) is found on almost all engines.

Notice the mounting holes:




Best 2 pictures I could find.

I also have a mint (80XXXkms accident car) 2000 civic ex throttle body for 40$ plus shipping. MAP and TPS included (and never removed from factory).

 

ok ill get a new tb then. the iacv is allready on there just need a throttle body now cause the auto one is weird. im sure the y8 manifold will fit the a6 but i just put it on a y7 that im putting in my rex.

 

yes the y8 manifold will fit the a6 as a matter of fact it'll fit any d series head, theres a write up on here i found long time ago on how to swap manifolds

 

im not sure about this but what about the 90 da tb