Fitting the Cowlis straight forward, but you will need an extended hub prop. Sam says to use a 4" prop extension, but everyone I talked to did not recommend any type of extension with a CS prop. I'm using a WW151 extended.
The plenum is another story. Calling it a PITA is being kind. One bit of advice, use Van's baffling kit. It will save you time. I was fortunate to benefit from Dave Hamilton's experience on an IO-360A1B. I visited his RV-8 and snapped over 60 digital photos. Even with these reference shots, the fit required a lot of cutting, reglassing and sweat.
I would do the cowl with no question, but the plenum would be copied from a website that uses Van's baffle kit and a fabricated aluminum top.
Thanks,
Robby Knox