z-bar question

On the subject of Z bars. I'm told that if you have a big block, that the z bar is different than for a small block. Is this true? I plan on calling Passon as you suggest but please answer if anyone knows.

I have actually thought long and hard about using the keisler juice clutch setup as people seem to rave about the low pedal effort. Are there any issues with using the hydraulic type (like pressure plate compatibility). I heard the fingers on the pressure plate need to be of a certian type and I don't know if that type is up to shifting when connected to a stroked 400 BB.

Sorry, didn't mean to hijack the thread. If I use the juice clutch, I won't even need the Z bar :-).