I recommend an intake duration of at least 230 @ .050 on a 114 lobe separation. .
Yep, and unless you have a cam custom ground, the RA4 grind is about as close to that as you'll find. Several cam grinders offer their version of the RA4 cam. The Melling SPC-8 from Ebay is always the cheapest--about $100 shipped.
And, if you're not gonna use Rhoads lifters, the Howard's 410051 or the Crower 60243 might be a better choice. They'll probably have a smoother idle than a RA4 grind without Rhoads lifters, because of slightly less advertised duration. The reason I prefer the Rhoads / RA4 combo is because it widens the power range, gives a smoother idle, more vac, and more bottom end torque. And the "ticking" sound doesn't bother me a bit--just part of the "High Performance" sound. Now I'm not posting links to the Summit site because they have the best price on all these cams, but because they have all the specs right there, easy to read.
Now for those who would like to get a cam custom ground to their own specs, Bullet Cams has a list of MANY possible lobes. They'll grind 'em like you want 'em.