Nothing was said about roller rockers though they are a positive add on to any engine and particulaly Ford as the rail type rocker tend to cause valve guide wear with other than stock camshafts. They look nice and minimize valve stem wear, reduce operational fiction, increase Hp, can change ratio from 1.6 to 1.7, weigh less, allowing the valves to not float in extreme high rpm operation plus look nice. You probably will need taller valve covers
Studs are converted to screw in from press in to prevent pull out, particularly with a non stock canshaft and higher rpm - and they WILL pull out. They are not bigger in diameter as both are 3/8, only the threaded portion is 7/16 though you can purchase 7/16 as well but not needed on a street engine.
These are bolt down rather then stud mounted Crane 1.7's on a late 5.0, but are similar in appearance