The Dorman 264-969 drivers side valve cover is an improvement over the original fbody dsvc.

 

Yep, couldn't use the dsvc on the LSX or 370 build because both builds have offset rocker arms on the intake valves.

 

Aren't the stock LS3 valve covers the same as LS1 and 5.3 valve covers? Are they taller?

 

No the baffling is different.

 

Spanks has the LS9 cover (taller cover) which have the same LS3 baffling pan but has more volume with the bumps to slow the air down I would also guess that the bumps act like a chambered muffler and knock the oil particles out of the air and back into the engine. They probably had some GM engineer do a plexiglass valve cover to study this situation and this is what they came up with. Why would you put bumps there in first place - they have a reason.