260H would be good,268H would be better. I have done the 268H in a 305 before. "Sounds like a 270H in a 350 at idle".
It was a real good combo and made good power. Or you could use one of the new Extreme series with close to the same specs.
The 110 lobe sep on the comps always sound good at idle if it is a decent size. Lot of midrange torque too.