5.3 what does it take to make them worth while??
Most head porters (TEA, etc) install larger 2.02" intake valves and retain the stock 1.50" exhaust valve. This becomes the well known 'Stage 1.5' you keep hearing about. Of course, a quality porting job is a nessesity along with unshrouding the valves. Unshrouding the valves is important on 5.3L heads since the chambers are smaller than on 5.7 heads. Stick in a set of 918 springs and stock retainers, and you should be good to go.
Ron,
Some folks with big cams worry about piston to valve clearance, and don't like to take too much of a cut on the head surfaces.
5.3 heads also will flow better than a 5.7 head on the exhaust side (if both heads have the same 1.50" exhaust valve and same porting technique)
Makes sense...

