IO360 in RV3
Mine was built in '84 down in Bakersfield by Gary Banducci and the Bakersfield Bunch. She had an O-360 and a CS prop for the first part of her life. She raced to some impressive times in the 90's, going in the range of 225 -228 at Sun-n-Fun. She qualified at Reno at 223 flown by Kevin Eldredge in 2001....there are other examples.
I bought her a few years ago with a fresh 160 hp IO-320 and a Sensinich prop. When I bought her, the landing gear was cracked and had been repaired a few times(which can be common, but worse with heavier engine). I had to completely rebuild the firewall forward with new parts to get her airworthy again. Not a small job.
My opinion: Unless you are racing, you don't need 190-200 hp, and lighter is better for ALL RV's. You don't need a CS prop unless you really just want it...It is a small single seater, and long trips in it are not that comfortable, and leaned out the fuel burn in mine is 6.5-7 gph at 160mph.
The big thing here is weight. Greater agility, less mass to land, less gear side loading in cross winds and better performance. Aim for under 800 lbs, skip the fancy and heavy auto pilot **** and other gadgets you don't really need. The RV-3 was Vans first....and the best flying one of them all. Don't over burden it with weight you don't need just to look cool. Flying mine is simple, and less costly and I have loads of fun with it.
If you do want to race...which I am considering bringing mine back into race trim, consider this: I have talked to F-1 pilots and others who know, and they agree the 360 and CS is too much weight. I am moving toward a LYCON overhaul to produce 190-200 hp at 3,200 RPM and a fixed pitch CATTO prop trimmed for 230mph at 7,000 density altitude(for Reno).
I have seen RV-4's and Harmon Rockets with LOADS of horsepower on the nose, and ultimately, these planes are limited by the airfoil of the wing. Even when clipped, like the Rocket, there is a point where it does not matter how much HP you have, the drag limits your top end.
Finally, if you just want to have fun...an 0-320 at 150 -160 hp will give you mind blowing performance and all the fun you can handle, consider widening the canopy to accommodate the extra wide RV-grin.
Cheers
Dave