There is hp to gain with a solid roller. A solid roller cam has much steeper ramps than a hydraulic cam so this requires a much stiffer valve spring with seat pressure being 185lbs and up depending on what cam you choose. The only downfall I see is if your running a 302 based motor you might have to pull the heads to install the taller solid roller lifters. This was the case on my 302 with Comp cams 288 solid roller cam. Also prolonged idling will starve the roller lifters of
oil and wear out the rollers prematurely.
Jeff