It can be done, i do research on push rod motors at the University of Central Florida and we have designed SBC and SBF motors to turn 9000+ RPM. The 302 should actually an easier motor to get up there, as the mass of the pushrods is a lot lighter due to the short deck height (compared to a 350/351). The problem with a high speed pushrod street motor that is that you are going to run it at the entire power band as you will not always be turning 7000rpm. When you design a high speed valve train for a pushrod motor, you are going to get valve loft and valve bounce - the valve bounce is what wipes your camshaft out or breaks valves. When we design these systems we focus on a particular power band and minimize the bounce while maximizing the loft. If you do not know the specifics of the valve train, under motored conditions (dynamic), you will not know where the valve train is bouncing on the camshaft nose or even over shooting the camshaft and crashing the valve into the valve seat.
I don't want to deter you from going after a project, but i just want to point out some potential problems that you may experience in your valve train.
Walz