There are some cars out there which run in stock type classes, which are forced to run stock heads. I'm thinking of this one car in particular. Its a 5.0 stang, running stock E5 heads. Those heads flow like CRAP. You think stock TR heads flow poorly? Check out those heads some time. They dont flow any more past .400 lift, yet this car runs a cam with about .700 lift. The reason is that with a higher lift cam, the valve is spending much more average time in the sweet zone for max flow. If you run a .400 lift cam, the valve only spends a moment at .400 lift, and the rest of the time at a lift where the heads are not flowing at thier peak. You run .700 lift, and now the heads are flowing at peak by the time the lifter is only halfway up the ramp. The only other way to get more air in the motor with a cam, is to run alot more duration. Run alot more duration, and now you end up with increased overlap. Top that off with the valve closing much later after bottom dead center. Now you're bleeding off major cylinder pressure, losing all this low end and now you have a powerband about 1000rpm wide. Thats the main reason why naturally aspirated race motors run so much compression. Its to buy back some of the torque that was lost from bleeding off pressure, and gain some of the curve back. So dont sweat running an extra spark plug gap's worth of lift. As long as you check piston to valve clearance and cap to guide/seal clearance, you'll be fine. I would go for a beehive spring setup personally. You wont have to run a ton of seat pressure. I know its a roller, so who cares, but running more pressure than you need to causes parasitic power loss from friction, and even if its not alot of power, its hard on parts.
