Don't think you'd loose power as such. You would likely end up with a flat spot somewhere in the Rev range where fueling allows for the iab butterflies on the stock intake manifold. And yes you can install the cams onto the standard valve springs. You will simply need to keep the Rev limit conservative. Say around 8500rpm maximum. If you were to install dual valve springs on the exhaust side also. You could happily raise the Rev limit to say 9000rpm. And make a few more hp.