comp cam xe-268h
I ran the XE 262 (just one size down) cam on a 360 in one of my trucks and had just the slightest bit of lope at 750 RPM. I had headers but no cross over pipe and one of my friends said that it sounded like a V8 speedboat at idle. I'm guessing that with 20 ci less displacement and 6 degrees more duration, you'll have just the lope you're looking for, but still decent low end torque and vacuum. With the XE series cam, I would recommend adjustable valve gear. Even with my itty-bitty cam, I had too much lifter pre-load, so I went with ductile iron adjustable rockers.