I had a comp XE262 in a 360, and it was very streetable, with only a mild lope, so the extra 80" of displacement should really tame down the low RPM drivability.
IIRC lunati recommends dual springs which will require machining the head...but their springs spec pretty close to the comp 911, which should drop on, and even use the factory retainer.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
