The 74" Hartzell blended airfoil prop is definitely what you want on an RV-8 for sure.
It's a little bit faster than the 72", and if in the future you ever need to have any repairs done to the blade tips, you can cut the 74" as far down to 72" and still be within overhaul specifications according to Hartzell. The 72" is already at minimum blade length already and cannot be shortened any more, according to Hartzell's documentation.
An RV-8 has plenty of ground clearance with the 74". If you ever find yourself nosed over enough to hit the prop, then you're already nosed over so far you're probably already in the process of flipping the plane over anyway, so that extra 1" ground clearance that the 72" prop gives you is a moot point.
I've put about 100 hours on my friend's RV-8 (pic below) with ECI Titan IO-360 and 74" Hartzell prop and it is an absolute joy to fly. Got to fly it from Texas to Oshkosh and back in both 2010 and 2011.
Thanks for the reply. I was thinking that the preformance would be a little better...didn't think of the possible need to whittle one down although I did have to do that once, but that's another story.
