what would be the <U>best</U> tranny for a dohc zc engine fittin into a hf?

 

I like my Si.
ZC's are better for acceleration but highway drivings gonna be higher.

 

You should use a CRX or Civic Si transaxle. These have the shortest final drive of any of the available transaxles for that engine. It will rev high on the freeway, but that shouldn't really be a problem. I have a ZC with an Si transaxle in my 91 HF and it seems to be a decent balance of acceleration and fuel economy.