IMO clams really need strong lighting, I wouldn't try to house one without metal halides, as clams need lots of light to survive, but this is just my opinion and hopefully someone with maybe with PC's can share their experience.
It'll live. I've done a gold maxima, squamosa and a deresa under 120 watts of pc. and my roomate has kept his squam under 170 watts of pc for over a year without the clam dying and noticable growth. However i completely agree that you have better chances of survivial and sucess with halides and/or vho.
keep your clam close to the lights and make sure it gets direct lighting.