I have a ZC in an 88 HB. Just changed the EACV because the other on "hummed" it seemed to resonate at idle. The new one is fine once it warms up but when it is first started cold (70 degrees) it idles at 2000-2200 RPM for abount two minutes. It used to slow down much more quickly after startup. By the way its an 89 SI EACV. Looks just like the ZC and bolts right up.