As long as you stay with the glide, it will be soft on the bottom. A good combo change would be a solid lifter cam to change the rpm capability's, allowing more rpm in the lights combined with a steeper rear gear. Might even consider a converter change, to match a new cam, but that might not fit into what you want to spend?
The head flow and intake system will have a lot to do with how much more rpm you can get out of it. But you should be able to go at least 6200 rpm in the lights with a flat tappet cam and what you have.