We go even bigger and deliver a 457 if you like
No issues as long as its maintained and tuned right.
Power gains.. about 1.2 hp per cubic inch but that could jump as high as 2 hp per cid depending on how efficient your current setup is. (cam/heads)
We've picked up a little over 2hp per cubic inch on the last LS7 we stroked to a 457. I would call that unusual and lay blame on the previous build for not being all that it should have been. It was a preferred power vendor on tech that did the original setup for this guy and in their typical fashion delivered a sub-par engine. The customer was not happy with it called us and we took care of him. Not only was this engine cammed wrong ( by a vendor who is know for their cams, it was honed wrong as well and the engine burnt oil all the time, same vendor with the supposed best cams).
SO your power gains are subjective.. but we will gain as much as you possibly can given your application